diff --git a/.changeset/funny-drinks-scream.md b/.changeset/funny-drinks-scream.md
new file mode 100644
index 00000000000..4428ac8ba31
--- /dev/null
+++ b/.changeset/funny-drinks-scream.md
@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Refine existing type in Predicate.isTagged
diff --git a/packages/effect/src/Predicate.ts b/packages/effect/src/Predicate.ts
index b5ac5040cdc..b6f10388a4d 100644
--- a/packages/effect/src/Predicate.ts
+++ b/packages/effect/src/Predicate.ts
@@ -1164,8 +1164,8 @@ export const hasProperty: {
  * @since 2.0.0
  */
 export const isTagged: {
-  <K extends string>(tag: K): (self: unknown) => self is { _tag: K }
-  <K extends string>(self: unknown, tag: K): self is { _tag: K }
+  <K extends string>(tag: K): <T>(self: T) => self is T extends {} ? Extract<T, { _tag: K }> : T & { _tag: K }
+  <K extends string, T>(self: T, tag: K): self is T extends {} ? Extract<T, { _tag: K }> : T & { _tag: K }
 } = dual(
   2,
   <K extends string>(self: unknown, tag: K): self is { _tag: K } => hasProperty(self, "_tag") && self["_tag"] === tag
diff --git a/packages/effect/typetest/Predicate.tst.ts b/packages/effect/typetest/Predicate.tst.ts
index dc74a61d31d..a891aa33818 100644
--- a/packages/effect/typetest/Predicate.tst.ts
+++ b/packages/effect/typetest/Predicate.tst.ts
@@ -7,6 +7,8 @@ declare const unknowns: ReadonlyArray<unknown>
 declare const numberOrNull: ReadonlyArray<number | null>
 declare const numberOrUndefined: ReadonlyArray<number | undefined>
 declare const numberOrNullOrUndefined: ReadonlyArray<number | null | undefined>
+declare const tags: ReadonlyArray<{ _tag: "a"; a: string } | { _tag: "b"; b: string }>
+declare const tagsOrNumbers: ReadonlyArray<{ _tag: "a"; a: string } | { _tag: "b"; b: string } | number>
 
 describe("Predicate", () => {
   it("isString", () => {
@@ -56,7 +58,11 @@ describe("Predicate", () => {
   })
 
   it("isTagged", () => {
-    expect(anys.filter(Predicate.isTagged("a"))).type.toBe<Array<{ _tag: "a" }>>()
+    expect(anys.filter(Predicate.isTagged("a"))).type.toBe<Array<any>>()
+    expect(unknowns.filter(Predicate.isTagged("a"))).type.toBe<Array<{ _tag: "a" }>>()
+    expect(tags.filter(Predicate.isTagged("a"))).type.toBe<Array<{ _tag: "a"; a: string }>>()
+    expect(tagsOrNumbers.filter(Predicate.isTagged("a"))).type.toBe<Array<{ _tag: "a"; a: string }>>()
+    expect(numberOrNull.filter(Predicate.isTagged("a"))).type.toBe<Array<never>>()
   })
 
   it("isNullish", () => {