diff --git a/src/testTree.ts b/src/testTree.ts
index 3f35e8956..c08760f08 100644
--- a/src/testTree.ts
+++ b/src/testTree.ts
@@ -166,10 +166,12 @@ export class TestTree extends DisposableBase {
         vsChild.tags = uChild.tags.map(tag => new this._vscode.TestTag(tag));
       const hasLocation = uChild.location.line || uChild.location.column;
       if (hasLocation && (!vsChild.range || vsChild.range.start.line + 1 !== uChild.location.line)) {
-        const line = uChild.location.line;
-        vsChild.range = new this._vscode.Range(Math.max(line - 1, 0), 0, line, 0);
-      } else if (hasLocation && !vsChild.range) {
-        vsChild.range = undefined;
+        // Playwright counts lines starting at 1, but VS Code's Range API uses 0-based lines.
+        // I need to subtract 1 from both start and end - the original code only fixed the
+        // start line, so the range end was still off by one and bled into the next line.
+        // See: https://github.com/microsoft/playwright-vscode/issues/38911
+        const zeroBased = Math.max(uChild.location.line - 1, 0);
+        vsChild.range = new this._vscode.Range(zeroBased, 0, zeroBased, 0);
       }
     }
 
diff --git a/tests/location.spec.ts b/tests/location.spec.ts
new file mode 100644
index 000000000..e33bd6c39
--- /dev/null
+++ b/tests/location.spec.ts
@@ -0,0 +1,77 @@
+/**
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed 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 CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Regression test for https://github.com/microsoft/playwright-vscode/issues/38911
+ *
+ * I noticed that Playwright counts lines starting at 1, but VS Code's Range API
+ * uses 0-based line numbers (line 0 is the first line). The range end was still
+ * using the raw 1-based value, so every TestItem range stretched one line too far.
+ * These tests make sure both start and end are converted correctly.
+ */
+
+import { expect, test } from './utils';
+
+test('test item range start and end should both use 0-based line numbers', async ({ activate }) => {
+  const { testController } = await activate({
+    'playwright.config.js': `module.exports = { testDir: 'tests' }`,
+    'tests/test.spec.ts': `
+      import { test } from '@playwright/test';
+      test('first', async () => {});
+      test('second', async () => {});
+    `,
+  });
+
+  await testController.expandTestItems(/test\.spec\.ts/);
+  const [first] = testController.findTestItems(/first/);
+  const [second] = testController.findTestItems(/second/);
+
+  expect(first, 'first test item should exist').toBeTruthy();
+  expect(second, 'second test item should exist').toBeTruthy();
+
+  // start and end should be on the same line - if end is still 1-based it'll be one too high
+  expect(first.range!.start.line).toBe(first.range!.end.line);
+  expect(second.range!.start.line).toBe(second.range!.end.line);
+
+  // Playwright says 'first' is on line 3 (1-based), so VS Code should see it at line 2 (0-based)
+  expect(first.range!.start.line).toBe(2);
+  expect(second.range!.start.line).toBe(3);
+});
+
+test('nested describe block items should also use fully 0-based ranges', async ({ activate }) => {
+  const { testController } = await activate({
+    'playwright.config.js': `module.exports = { testDir: 'tests' }`,
+    'tests/auth.spec.ts': `
+      import { test } from '@playwright/test';
+      test.describe('auth', () => {
+        test('login', async () => {});
+        test('logout', async () => {});
+      });
+    `,
+  });
+
+  await testController.expandTestItems(/auth\.spec\.ts/);
+  await testController.expandTestItems(/auth/);
+  const [login] = testController.findTestItems(/login/);
+  const [logout] = testController.findTestItems(/logout/);
+
+  expect(login, 'login test item should exist').toBeTruthy();
+  expect(logout, 'logout test item should exist').toBeTruthy();
+
+  // same check as above - nested tests should also have matching start and end lines
+  expect(login.range!.start.line).toBe(login.range!.end.line);
+  expect(logout.range!.start.line).toBe(logout.range!.end.line);
+});