diff --git a/2nd-gen/packages/core/components/accordion/Accordion.base.ts b/2nd-gen/packages/core/components/accordion/Accordion.base.ts
new file mode 100644
index 00000000000..883ad39f1ea
--- /dev/null
+++ b/2nd-gen/packages/core/components/accordion/Accordion.base.ts
@@ -0,0 +1,208 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import { PropertyValues } from 'lit';
+import { property } from 'lit/decorators.js';
+
+import { SpectrumElement } from '@spectrum-web-components/core/element/index.js';
+import { SizedMixin } from '@spectrum-web-components/core/mixins/index.js';
+
+import {
+  ACCORDION_VALID_SIZES,
+  type AccordionDensity,
+  type AccordionHeadingLevel,
+  type AccordionSize,
+  SWC_ACCORDION_ITEM_TOGGLE_EVENT,
+} from './Accordion.types.js';
+import { AccordionItemBase } from './AccordionItem.base.js';
+
+/**
+ * Base class for accordion components. Manages item propagation, heading
+ * level, density, and the exclusive-open constraint.
+ *
+ * @attribute {boolean} allowMultiple - Reflected as `allow-multiple`. When set,
+ *   multiple items may be open at the same time.
+ * @attribute {number} level - Heading level (2–6) applied to every item header.
+ *   Values outside that range are clamped.
+ * @attribute {AccordionSize} size - Size applied to all items.
+ * @attribute {AccordionDensity} density - Vertical spacing between items.
+ * @attribute {boolean} quiet - Renders the accordion in its quiet visual variant.
+ * @attribute {boolean} disabled - Disables all items in the accordion.
+ *
+ * @slot - One or more `swc-accordion-item` elements.
+ */
+export abstract class AccordionBase extends SizedMixin(SpectrumElement, {
+  validSizes: ACCORDION_VALID_SIZES,
+  defaultSize: 'm',
+}) {
+  // ──────────────────
+  //     PUBLIC API
+  // ──────────────────
+
+  /**
+   * When set, multiple items may be open at the same time. By default only
+   * one item can be open.
+   */
+  @property({ type: Boolean, reflect: true, attribute: 'allow-multiple' })
+  public allowMultiple: boolean = false;
+
+  /**
+   * Heading level applied to every item header (2–6). Defaults to 3.
+   * Values outside that range are clamped.
+   */
+  @property({ type: Number, reflect: true })
+  public level: AccordionHeadingLevel = 3;
+
+  /**
+   * Size applied to all items. Defaults to `m`.
+   */
+  declare public size: AccordionSize;
+
+  /**
+   * Controls vertical spacing between items.
+   *
+   * @default regular
+   */
+  @property({ type: String, reflect: true })
+  public density: AccordionDensity = 'regular';
+
+  /**
+   * Renders the accordion in its quiet (no-border) visual variant.
+   */
+  @property({ type: Boolean, reflect: true })
+  public quiet: boolean = false;
+
+  /**
+   * Disables all items in the accordion. Individual items may also be
+   * disabled independently.
+   */
+  @property({ type: Boolean, reflect: true })
+  public disabled: boolean = false;
+
+  // ──────────────────────
+  //     IMPLEMENTATION
+  // ──────────────────────
+
+  private assignedItems(): AccordionItemBase[] {
+    const slot = this.renderRoot?.querySelector('slot');
+    if (!slot) {
+      return [];
+    }
+    return slot
+      .assignedElements({ flatten: true })
+      .filter((el): el is AccordionItemBase => el instanceof AccordionItemBase);
+  }
+
+  private closeSiblingsOnOpen = (event: Event): void => {
+    if (this.disabled) {
+      event.preventDefault();
+      return;
+    }
+    if (this.allowMultiple) {
+      return;
+    }
+    const toggling = event.target;
+    if (!(toggling instanceof AccordionItemBase)) {
+      return;
+    }
+    // Defer until after dispatch returns so that a canceled toggle (where the
+    // item reverts open back to false) does not incorrectly close siblings.
+    queueMicrotask(() => {
+      if (!toggling.open) {
+        return;
+      }
+      for (const item of this.assignedItems()) {
+        if (item !== toggling) {
+          item.open = false;
+        }
+      }
+    });
+  };
+
+  protected syncAccordionItems(): void {
+    for (const item of this.assignedItems()) {
+      item.setManagedHeading(this.level);
+      item.size = this.size;
+      item.setManagedParentDisabled(this.disabled);
+    }
+  }
+
+  private enforceExclusiveOpen(): void {
+    let foundOpen = false;
+    for (const item of this.assignedItems()) {
+      if (item.open) {
+        if (foundOpen) {
+          item.open = false;
+        } else {
+          foundOpen = true;
+        }
+      }
+    }
+  }
+
+  public override connectedCallback(): void {
+    super.connectedCallback();
+    this.addEventListener(
+      SWC_ACCORDION_ITEM_TOGGLE_EVENT,
+      this.closeSiblingsOnOpen
+    );
+  }
+
+  public override disconnectedCallback(): void {
+    super.disconnectedCallback();
+    this.removeEventListener(
+      SWC_ACCORDION_ITEM_TOGGLE_EVENT,
+      this.closeSiblingsOnOpen
+    );
+  }
+
+  protected override update(changedProperties: PropertyValues): void {
+    if (changedProperties.has('level')) {
+      const clamped = Math.min(
+        6,
+        Math.max(2, this.level)
+      ) as AccordionHeadingLevel;
+      if (this.level !== clamped) {
+        this.level = clamped;
+      }
+    }
+    if (
+      changedProperties.has('level') ||
+      changedProperties.has('size') ||
+      changedProperties.has('disabled')
+    ) {
+      this.syncAccordionItems();
+    }
+    // changedProperties.get() returns the previous value; this fires only when
+    // disabled transitions from true → false (re-enable).
+    if (
+      changedProperties.has('disabled') &&
+      changedProperties.get('disabled') === true &&
+      !this.allowMultiple
+    ) {
+      this.enforceExclusiveOpen();
+    }
+    super.update(changedProperties);
+  }
+
+  protected override firstUpdated(changedProperties: PropertyValues): void {
+    super.firstUpdated(changedProperties);
+    if (window.__swc?.DEBUG && !this.hasAttribute('density')) {
+      window.__swc.warn(
+        this,
+        `<${this.localName}> should have an explicit "density" attribute set. Defaulting to "regular".`,
+        'https://opensource.adobe.com/spectrum-web-components/components/accordion/',
+        { type: 'api', level: 'low' }
+      );
+    }
+  }
+}
diff --git a/2nd-gen/packages/core/components/accordion/Accordion.types.ts b/2nd-gen/packages/core/components/accordion/Accordion.types.ts
new file mode 100644
index 00000000000..fbf4da59f9b
--- /dev/null
+++ b/2nd-gen/packages/core/components/accordion/Accordion.types.ts
@@ -0,0 +1,33 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import type { ElementSize } from '@spectrum-web-components/core/mixins/index.js';
+
+export const ACCORDION_VALID_SIZES = [
+  's',
+  'm',
+  'l',
+  'xl',
+] as const satisfies readonly ElementSize[];
+export type AccordionSize = (typeof ACCORDION_VALID_SIZES)[number];
+
+export const ACCORDION_DENSITIES = ['compact', 'regular', 'spacious'] as const;
+export type AccordionDensity = (typeof ACCORDION_DENSITIES)[number];
+
+export const ACCORDION_HEADING_LEVELS = [2, 3, 4, 5, 6] as const;
+export type AccordionHeadingLevel = (typeof ACCORDION_HEADING_LEVELS)[number];
+
+export const SWC_ACCORDION_ITEM_TOGGLE_EVENT = 'swc-accordion-item-toggle';
+export const SWC_ACCORDION_ITEM_OPEN_EVENT = 'swc-open';
+export const SWC_ACCORDION_ITEM_CLOSE_EVENT = 'swc-close';
+export const SWC_ACCORDION_ITEM_AFTER_OPEN_EVENT = 'swc-after-open';
+export const SWC_ACCORDION_ITEM_AFTER_CLOSE_EVENT = 'swc-after-close';
diff --git a/2nd-gen/packages/core/components/accordion/AccordionItem.base.ts b/2nd-gen/packages/core/components/accordion/AccordionItem.base.ts
new file mode 100644
index 00000000000..950f61cf9c2
--- /dev/null
+++ b/2nd-gen/packages/core/components/accordion/AccordionItem.base.ts
@@ -0,0 +1,183 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import { property, state } from 'lit/decorators.js';
+
+import { SpectrumElement } from '@spectrum-web-components/core/element/index.js';
+import { ObserveSlotPresence } from '@spectrum-web-components/core/mixins/observe-slot-presence.js';
+
+import {
+  type AccordionHeadingLevel,
+  type AccordionSize,
+  SWC_ACCORDION_ITEM_AFTER_CLOSE_EVENT,
+  SWC_ACCORDION_ITEM_AFTER_OPEN_EVENT,
+  SWC_ACCORDION_ITEM_CLOSE_EVENT,
+  SWC_ACCORDION_ITEM_OPEN_EVENT,
+  SWC_ACCORDION_ITEM_TOGGLE_EVENT,
+} from './Accordion.types.js';
+
+/**
+ * Base class for accordion item components. Manages open/disabled state,
+ * heading level (set by the parent accordion), and the toggle event.
+ *
+ * @attribute {boolean} open - Whether the accordion item panel is expanded.
+ * @attribute {boolean} disabled - Whether the accordion item is disabled.
+ * @attribute {AccordionSize} size - Size of the item. Inherited from the parent
+ *   accordion when slotted; controls the chevron icon when used standalone.
+ *
+ * @slot label - The heading text for this accordion item.
+ * @slot actions - Optional actions rendered adjacent to the heading, outside
+ *   the toggle button so they remain independently interactive.
+ * @slot - The panel content revealed when the item is open.
+ */
+export abstract class AccordionItemBase extends ObserveSlotPresence(
+  SpectrumElement,
+  '[slot="actions"]'
+) {
+  // ──────────────────
+  //     PUBLIC API
+  // ──────────────────
+
+  /**
+   * Whether the accordion item panel is expanded.
+   */
+  @property({ type: Boolean, reflect: true })
+  public get open(): boolean {
+    return this._open;
+  }
+
+  public set open(value: boolean) {
+    if (this.hasUpdated && !this.mayExpand() && value !== this._open) {
+      return;
+    }
+    if (value === this._open) {
+      return;
+    }
+    const oldValue = this._open;
+    this._open = value;
+    if (value) {
+      this.setAttribute('open', '');
+    } else {
+      this.removeAttribute('open');
+    }
+    this.requestUpdate('open', oldValue);
+  }
+
+  /**
+   * Whether the accordion item is disabled. A disabled item keeps its header
+   * in the tab order but blocks toggling.
+   */
+  @property({ type: Boolean, reflect: true })
+  public disabled: boolean = false;
+
+  /**
+   * The size of the item. Inherited from the parent accordion; controls which
+   * chevron icon is displayed. Has no effect when the item is used standalone.
+   */
+  @property({ type: String, reflect: true })
+  public size?: AccordionSize;
+
+  private _open = false;
+
+  // ──────────────────────
+  //     INTERNAL STATE
+  // ──────────────────────
+
+  /**
+   * @internal
+   * Heading level (2–6) propagated by the parent accordion. Defaults to 3
+   * for standalone items.
+   */
+  @state()
+  protected headingLevel: AccordionHeadingLevel = 3;
+
+  /**
+   * @internal
+   * Set by the parent accordion when its own `disabled` is true. Causes the
+   * item to render as disabled (aria-disabled + inert panel) without clobbering
+   * the item's own `disabled` property, so the per-item state is preserved
+   * when the accordion is re-enabled.
+   */
+  @state()
+  protected parentDisabled: boolean = false;
+
+  // ──────────────────────
+  //     IMPLEMENTATION
+  // ──────────────────────
+
+  /**
+   * @internal
+   * Whether the item may change `open` (expand or collapse). When false, the
+   * `open` setter and `toggle()` leave state unchanged.
+   */
+  protected mayExpand(): boolean {
+    return !this.disabled && !this.parentDisabled;
+  }
+
+  /**
+   * @internal
+   * Toggles the item open state. Guards for disabled, flips `open`, dispatches
+   * the toggle event, and reverts if the event is canceled. On success, dispatches
+   * `swc-after-open` or `swc-after-close` after the next render cycle.
+   */
+  protected toggle(): void {
+    if (!this.mayExpand()) {
+      return;
+    }
+    this.open = !this.open;
+    const toggleEvent = new Event(SWC_ACCORDION_ITEM_TOGGLE_EVENT, {
+      bubbles: true,
+      composed: true,
+      cancelable: true,
+    });
+    if (!this.dispatchEvent(toggleEvent)) {
+      this.open = !this.open;
+      return;
+    }
+    const isOpen = this.open;
+    this.dispatchEvent(
+      new Event(
+        isOpen ? SWC_ACCORDION_ITEM_OPEN_EVENT : SWC_ACCORDION_ITEM_CLOSE_EVENT,
+        {
+          bubbles: true,
+          composed: true,
+        }
+      )
+    );
+    void this.updateComplete.then(() => {
+      this.dispatchEvent(
+        new Event(
+          isOpen
+            ? SWC_ACCORDION_ITEM_AFTER_OPEN_EVENT
+            : SWC_ACCORDION_ITEM_AFTER_CLOSE_EVENT,
+          { bubbles: true, composed: true }
+        )
+      );
+    });
+  }
+
+  /**
+   * @internal
+   * Synchronizes parent-managed heading level onto the item.
+   */
+  public setManagedHeading(heading: AccordionHeadingLevel): void {
+    this.headingLevel = heading;
+  }
+
+  /**
+   * @internal
+   * Synchronizes parent-managed disabled state onto the item.
+   */
+  public setManagedParentDisabled(disabled: boolean): void {
+    this.parentDisabled = disabled;
+  }
+}
diff --git a/2nd-gen/packages/core/components/accordion/index.ts b/2nd-gen/packages/core/components/accordion/index.ts
new file mode 100644
index 00000000000..058e18a5674
--- /dev/null
+++ b/2nd-gen/packages/core/components/accordion/index.ts
@@ -0,0 +1,15 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+export * from './Accordion.base.js';
+export * from './AccordionItem.base.js';
+export * from './Accordion.types.js';
diff --git a/2nd-gen/packages/core/package.json b/2nd-gen/packages/core/package.json
index 86b4009e996..b4626a67e89 100644
--- a/2nd-gen/packages/core/package.json
+++ b/2nd-gen/packages/core/package.json
@@ -19,6 +19,10 @@
       "types": "./dist/components/alert-banner/index.d.ts",
       "import": "./dist/components/alert-banner/index.js"
     },
+    "./components/accordion": {
+      "types": "./dist/components/accordion/index.d.ts",
+      "import": "./dist/components/accordion/index.js"
+    },
     "./components/asset": {
       "types": "./dist/components/asset/index.d.ts",
       "import": "./dist/components/asset/index.js"
@@ -148,6 +152,9 @@
       "components/alert-banner": [
         "dist/components/alert-banner/index.d.ts"
       ],
+      "components/accordion": [
+        "dist/components/accordion/index.d.ts"
+      ],
       "components/asset": [
         "dist/components/asset/index.d.ts"
       ],
diff --git a/2nd-gen/packages/swc/.storybook/preview.ts b/2nd-gen/packages/swc/.storybook/preview.ts
index 73e4673e0ab..68e75baf54d 100644
--- a/2nd-gen/packages/swc/.storybook/preview.ts
+++ b/2nd-gen/packages/swc/.storybook/preview.ts
@@ -324,11 +324,7 @@ const preview = {
               'Components',
               [
                 'Accordion',
-                [
-                  'Accessibility migration analysis',
-                  'Migration plan',
-                  'Rendering and styling migration analysis',
-                ],
+                ['Accessibility migration analysis', 'Migration plan'],
                 'Action button',
                 ['Rendering and styling migration analysis'],
                 'Action group',
diff --git a/2nd-gen/packages/swc/components/accordion/Accordion.ts b/2nd-gen/packages/swc/components/accordion/Accordion.ts
new file mode 100644
index 00000000000..92d112150e6
--- /dev/null
+++ b/2nd-gen/packages/swc/components/accordion/Accordion.ts
@@ -0,0 +1,45 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import { CSSResultArray, html, TemplateResult } from 'lit';
+
+import { AccordionBase } from '@spectrum-web-components/core/components/accordion';
+
+import styles from './accordion.css';
+
+/**
+ * An accordion component that groups expandable content sections.
+ *
+ * @element swc-accordion
+ * @since 2.0.0
+ *
+ * @example
+ * <swc-accordion density="regular">
+ *   <swc-accordion-item>
+ *     <span slot="label">Section heading</span>
+ *     Panel content goes here.
+ *   </swc-accordion-item>
+ * </swc-accordion>
+ */
+export class Accordion extends AccordionBase {
+  public static override get styles(): CSSResultArray {
+    return [styles];
+  }
+
+  protected override render(): TemplateResult {
+    return html`
+      <div class="swc-Accordion">
+        <slot @slotchange=${this.syncAccordionItems}></slot>
+      </div>
+    `;
+  }
+}
diff --git a/2nd-gen/packages/swc/components/accordion/AccordionItem.ts b/2nd-gen/packages/swc/components/accordion/AccordionItem.ts
new file mode 100644
index 00000000000..2979fe29ef6
--- /dev/null
+++ b/2nd-gen/packages/swc/components/accordion/AccordionItem.ts
@@ -0,0 +1,149 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import { CSSResultArray, html, TemplateResult } from 'lit';
+import { ifDefined } from 'lit/directives/if-defined.js';
+import { when } from 'lit/directives/when.js';
+import { html as staticHtml, unsafeStatic } from 'lit/static-html.js';
+
+import { AccordionItemBase } from '@spectrum-web-components/core/components/accordion';
+
+import '../icon/swc-icon.js';
+
+import { Chevron75Icon } from '../icon/elements/Chevron75Icon.js';
+import { Chevron100Icon } from '../icon/elements/Chevron100Icon.js';
+import { Chevron200Icon } from '../icon/elements/Chevron200Icon.js';
+import { Chevron300Icon } from '../icon/elements/Chevron300Icon.js';
+
+import styles from './accordion.css';
+
+/**
+ * An accordion item component that wraps a single expandable content section.
+ *
+ * @element swc-accordion-item
+ * @since 2.0.0
+ *
+ * @fires swc-accordion-item-toggle - Dispatched when the item open state is
+ *   toggled. Cancelable; `preventDefault()` reverts the change.
+ * @fires swc-open - Dispatched when the item begins opening.
+ * @fires swc-close - Dispatched when the item begins closing.
+ * @fires swc-after-open - Dispatched after the item has fully opened.
+ * @fires swc-after-close - Dispatched after the item has fully closed.
+ *
+ * @example
+ * <swc-accordion-item>
+ *   <span slot="label">Section heading</span>
+ *   Panel content goes here.
+ * </swc-accordion-item>
+ */
+export class AccordionItem extends AccordionItemBase {
+  // ──────────────────────────────
+  //     STYLING
+  // ──────────────────────────────
+
+  public static override get styles(): CSSResultArray {
+    return [styles];
+  }
+
+  // ──────────────────────────────
+  //     DELEGATION
+  // ──────────────────────────────
+
+  public override focus(options?: FocusOptions): void {
+    this.shadowRoot?.getElementById('header')?.focus(options);
+  }
+
+  public override click(): void {
+    this.shadowRoot?.getElementById('header')?.click();
+  }
+
+  // ──────────────────────────────
+  //     RENDERING
+  // ──────────────────────────────
+
+  private chevronForSize(): TemplateResult {
+    switch (this.size) {
+      case 's':
+        return Chevron75Icon();
+      case 'l':
+        return Chevron200Icon();
+      case 'xl':
+        return Chevron300Icon();
+      case 'm':
+      default:
+        return Chevron100Icon();
+    }
+  }
+
+  private handleHeaderKeydown(event: Event): void {
+    if ((event as KeyboardEvent).key === ' ') {
+      // Space requires preventDefault to suppress page scroll; toggle is then
+      // called explicitly. Enter is not handled here — the browser's native
+      // button activation fires a click event, which calls toggle() via the
+      // @click binding.
+      event.preventDefault();
+      this.toggle();
+    }
+  }
+
+  private renderHeadingWrapper(content: TemplateResult): TemplateResult {
+    const tag = unsafeStatic(`h${this.headingLevel}`);
+    return staticHtml`<${tag} class="swc-AccordionItem-heading">${content}</${tag}>`;
+  }
+
+  protected override render(): TemplateResult {
+    const button = html`
+      <button
+        id="header"
+        class="swc-AccordionItem-header"
+        type="button"
+        aria-expanded=${this.open ? 'true' : 'false'}
+        aria-controls="content"
+        aria-disabled=${ifDefined(
+          this.disabled || this.parentDisabled ? 'true' : undefined
+        )}
+        @click=${this.toggle}
+        @keydown=${this.handleHeaderKeydown}
+      >
+        <swc-icon class="swc-AccordionItem-indicator" aria-hidden="true">
+          ${this.chevronForSize()}
+        </swc-icon>
+        <span class="swc-AccordionItem-label">
+          <slot name="label"></slot>
+        </span>
+      </button>
+    `;
+    return html`
+      <div class="swc-AccordionItem">
+        ${this.renderHeadingWrapper(button)}
+        ${when(
+          this.slotContentIsPresent,
+          () => html`
+            <div class="swc-AccordionItem-actions">
+              <slot name="actions"></slot>
+            </div>
+          `
+        )}
+        <div
+          id="content"
+          class="swc-AccordionItem-content"
+          role="region"
+          aria-labelledby="header"
+          ?hidden=${!this.open}
+          .inert=${this.disabled || this.parentDisabled}
+        >
+          <slot></slot>
+        </div>
+      </div>
+    `;
+  }
+}
diff --git a/2nd-gen/packages/swc/components/accordion/accordion.css b/2nd-gen/packages/swc/components/accordion/accordion.css
new file mode 100644
index 00000000000..40f33594a28
--- /dev/null
+++ b/2nd-gen/packages/swc/components/accordion/accordion.css
@@ -0,0 +1,13 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+/* S2 token imports and selector definitions land here in Phase 4. */
diff --git a/2nd-gen/packages/swc/components/accordion/index.ts b/2nd-gen/packages/swc/components/accordion/index.ts
new file mode 100644
index 00000000000..f8f7131062c
--- /dev/null
+++ b/2nd-gen/packages/swc/components/accordion/index.ts
@@ -0,0 +1,14 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+export * from './Accordion.js';
+export * from './AccordionItem.js';
diff --git a/2nd-gen/packages/swc/components/accordion/stories/accordion.stories.ts b/2nd-gen/packages/swc/components/accordion/stories/accordion.stories.ts
new file mode 100644
index 00000000000..4284e11925e
--- /dev/null
+++ b/2nd-gen/packages/swc/components/accordion/stories/accordion.stories.ts
@@ -0,0 +1,127 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import { html } from 'lit';
+import type { Meta, StoryObj as Story } from '@storybook/web-components';
+import { getStorybookHelpers } from '@wc-toolkit/storybook-helpers';
+
+import '@adobe/spectrum-wc/components/accordion/swc-accordion.js';
+import '@adobe/spectrum-wc/components/accordion/swc-accordion-item.js';
+
+import {
+  ACCORDION_DENSITIES,
+  ACCORDION_VALID_SIZES,
+  SWC_ACCORDION_ITEM_TOGGLE_EVENT,
+} from '../../../../core/components/accordion/Accordion.types.js';
+
+// ────────────────
+//    METADATA
+// ────────────────
+
+const { args, argTypes, template } = getStorybookHelpers('swc-accordion');
+
+argTypes.density = {
+  ...argTypes.density,
+  control: { type: 'select' },
+  options: [...ACCORDION_DENSITIES],
+  table: {
+    ...argTypes.density?.table,
+    category: 'attributes',
+    defaultValue: { summary: 'regular' },
+  },
+};
+
+argTypes.size = {
+  ...argTypes.size,
+  control: { type: 'select' },
+  options: ['', ...ACCORDION_VALID_SIZES],
+  table: {
+    ...argTypes.size?.table,
+    category: 'attributes',
+  },
+};
+
+argTypes.level = {
+  ...argTypes.level,
+  control: { type: 'number', min: 2, max: 6 },
+  table: {
+    ...argTypes.level?.table,
+    category: 'attributes',
+    defaultValue: { summary: '3' },
+  },
+};
+
+const defaultItems = html`
+  <swc-accordion-item>
+    <span slot="label">Alchemy</span>
+    Alchemy is an ancient branch of natural philosophy, a philosophical and
+    protoscientific tradition that was historically practiced in China, India,
+    the Muslim world, and Europe.
+  </swc-accordion-item>
+  <swc-accordion-item>
+    <span slot="label">Astrology</span>
+    Astrology is a range of divinatory practices, recognized as pseudoscientific
+    since the 18th century, that propose that information about human affairs
+    and terrestrial events may be discerned by studying the apparent positions
+    of celestial objects.
+  </swc-accordion-item>
+  <swc-accordion-item open>
+    <span slot="label">Natural magic</span>
+    Natural magic in the context of early modern Europe was a branch of
+    philosophy that treated occult forces as resulting from natural causes, not
+    from divine or demonic intervention.
+  </swc-accordion-item>
+`;
+
+/**
+ * An accordion groups related content sections, each behind a header that can
+ * be expanded or collapsed. Only one section is open at a time by default;
+ * set `allow-multiple` to let any number of sections be open simultaneously.
+ */
+const meta: Meta = {
+  title: 'Accordion',
+  component: 'swc-accordion',
+  args,
+  argTypes,
+  render: (args) => template(args, defaultItems),
+  parameters: {
+    actions: { handles: [SWC_ACCORDION_ITEM_TOGGLE_EVENT] },
+    docs: {
+      subtitle: 'Groups related content sections behind expandable headers.',
+    },
+  },
+  tags: ['migrated'],
+};
+
+export default meta;
+
+// ────────────────────
+//    AUTODOCS STORY
+// ────────────────────
+
+export const Playground: Story = {
+  args: {
+    density: 'regular',
+  },
+  tags: ['autodocs', 'dev'],
+};
+
+// ──────────────────────────
+//    OVERVIEW STORY
+// ──────────────────────────
+
+export const Overview: Story = {
+  args: {
+    density: 'regular',
+  },
+  tags: ['overview'],
+};
diff --git a/2nd-gen/packages/swc/components/accordion/swc-accordion-item.ts b/2nd-gen/packages/swc/components/accordion/swc-accordion-item.ts
new file mode 100644
index 00000000000..cd9853027e7
--- /dev/null
+++ b/2nd-gen/packages/swc/components/accordion/swc-accordion-item.ts
@@ -0,0 +1,23 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import { defineElement } from '@spectrum-web-components/core/element/index.js';
+
+import { AccordionItem } from './AccordionItem.js';
+
+declare global {
+  interface HTMLElementTagNameMap {
+    'swc-accordion-item': AccordionItem;
+  }
+}
+
+defineElement('swc-accordion-item', AccordionItem);
diff --git a/2nd-gen/packages/swc/components/accordion/swc-accordion.ts b/2nd-gen/packages/swc/components/accordion/swc-accordion.ts
new file mode 100644
index 00000000000..d51f7f1b1e5
--- /dev/null
+++ b/2nd-gen/packages/swc/components/accordion/swc-accordion.ts
@@ -0,0 +1,23 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import { defineElement } from '@spectrum-web-components/core/element/index.js';
+
+import { Accordion } from './Accordion.js';
+
+declare global {
+  interface HTMLElementTagNameMap {
+    'swc-accordion': Accordion;
+  }
+}
+
+defineElement('swc-accordion', Accordion);
diff --git a/2nd-gen/packages/swc/components/accordion/test/.gitkeep b/2nd-gen/packages/swc/components/accordion/test/.gitkeep
new file mode 100644
index 00000000000..8b137891791
--- /dev/null
+++ b/2nd-gen/packages/swc/components/accordion/test/.gitkeep
@@ -0,0 +1 @@
+
diff --git a/2nd-gen/packages/swc/components/icon/elements/Chevron300Icon.ts b/2nd-gen/packages/swc/components/icon/elements/Chevron300Icon.ts
new file mode 100644
index 00000000000..72956bf4b1d
--- /dev/null
+++ b/2nd-gen/packages/swc/components/icon/elements/Chevron300Icon.ts
@@ -0,0 +1,22 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+import { html, TemplateResult } from 'lit';
+
+export const Chevron300Icon = (): TemplateResult => {
+  return html`
+    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 14 14">
+      <path
+        d="M10.639 7a.95.95 0 0 0-.278-.671l-.003-.002-5.33-5.33a.95.95 0 0 0-1.342 1.342L8.346 7l-4.661 4.66a.95.95 0 1 0 1.342 1.343l5.33-5.33.003-.001A.95.95 0 0 0 10.64 7z"
+      />
+    </svg>
+  `;
+};
diff --git a/2nd-gen/packages/swc/components/icon/elements/index.ts b/2nd-gen/packages/swc/components/icon/elements/index.ts
index b30f66ddd2c..8d6cf638b2f 100644
--- a/2nd-gen/packages/swc/components/icon/elements/index.ts
+++ b/2nd-gen/packages/swc/components/icon/elements/index.ts
@@ -20,6 +20,7 @@ export * from './Chevron50Icon.js';
 export * from './Chevron75Icon.js';
 export * from './Chevron100Icon.js';
 export * from './Chevron200Icon.js';
+export * from './Chevron300Icon.js';
 export * from './CornerTriangle300Icon.js';
 export * from './Cross75Icon.js';
 export * from './Cross100Icon.js';