diff --git a/.changeset/silly-eagles-unite.md b/.changeset/silly-eagles-unite.md
new file mode 100644
index 00000000000..4b5989200b0
--- /dev/null
+++ b/.changeset/silly-eagles-unite.md
@@ -0,0 +1,7 @@
+---
+"@firebase/database-compat": major
+"@firebase/database-types": major
+"@firebase/database": major
+---
+
+Updated type of action parameter for DataSnapshot#forEach
diff --git a/common/api-review/database.api.md b/common/api-review/database.api.md
index 8b3ef1ac7fb..4a98aea3d4e 100644
--- a/common/api-review/database.api.md
+++ b/common/api-review/database.api.md
@@ -33,7 +33,7 @@ export class DataSnapshot {
     child(path: string): DataSnapshot;
     exists(): boolean;
     exportVal(): any;
-    forEach(action: (child: DataSnapshot) => boolean | void): boolean;
+    forEach(action: (child: IteratedDataSnapshot) => boolean | void): boolean;
     hasChild(path: string): boolean;
     hasChildren(): boolean;
     get key(): string | null;
@@ -85,6 +85,12 @@ export function goOnline(db: Database): void;
 // @public
 export function increment(delta: number): object;
 
+// @public
+export interface IteratedDataSnapshot extends DataSnapshot {
+    // (undocumented)
+    key: string;
+}
+
 // @public
 export function limitToFirst(limit: number): QueryConstraint;
 
diff --git a/packages/database-compat/src/api/Reference.ts b/packages/database-compat/src/api/Reference.ts
index 3f9bb63b8ff..c4846b8ee60 100644
--- a/packages/database-compat/src/api/Reference.ts
+++ b/packages/database-compat/src/api/Reference.ts
@@ -164,7 +164,7 @@ export class DataSnapshot implements Compat<ModularDataSnapshot> {
    * @returns True if forEach was canceled by action returning true for
    * one of the child nodes.
    */
-  forEach(action: (snapshot: DataSnapshot) => boolean | void): boolean {
+  forEach(action: (snapshot: IteratedDataSnapshot) => boolean | void): boolean {
     validateArgCount('DataSnapshot.forEach', 1, 1, arguments.length);
     validateCallback('DataSnapshot.forEach', 'action', action, false);
     return this._delegate.forEach(expDataSnapshot =>
@@ -208,6 +208,13 @@ export class DataSnapshot implements Compat<ModularDataSnapshot> {
   }
 }
 
+/**
+ * Represents a child snapshot of a `Reference` that is being iterated over. The key will never be undefined.
+ */
+export interface IteratedDataSnapshot extends DataSnapshot {
+  key: string; // key of the location of this snapshot.
+}
+
 export interface SnapshotCallback {
   (dataSnapshot: DataSnapshot, previousChildName?: string | null): unknown;
 }
diff --git a/packages/database-types/index.d.ts b/packages/database-types/index.d.ts
index 680a4a540b8..f304a4ed5b3 100644
--- a/packages/database-types/index.d.ts
+++ b/packages/database-types/index.d.ts
@@ -18,11 +18,18 @@
 import { FirebaseApp } from '@firebase/app-types';
 import { EmulatorMockTokenOptions } from '@firebase/util';
 
+/**
+ * Represents a child snapshot of a `Reference` that is being iterated over. The key will never be undefined.
+ */
+export interface IteratedDataSnapshot extends DataSnapshot {
+  key: string; // key of the location of this snapshot.
+}
+
 export interface DataSnapshot {
   child(path: string): DataSnapshot;
   exists(): boolean;
   exportVal(): any;
-  forEach(action: (a: DataSnapshot) => boolean | void): boolean;
+  forEach(action: (a: IteratedDataSnapshot) => boolean | void): boolean;
   getPriority(): string | number | null;
   hasChild(path: string): boolean;
   hasChildren(): boolean;
diff --git a/packages/database/src/api.standalone.ts b/packages/database/src/api.standalone.ts
index 876ec67c441..c7726143f16 100644
--- a/packages/database/src/api.standalone.ts
+++ b/packages/database/src/api.standalone.ts
@@ -37,6 +37,7 @@ export { OnDisconnect } from './api/OnDisconnect';
 export {
   DataSnapshot,
   EventType,
+  IteratedDataSnapshot,
   QueryConstraint,
   QueryConstraintType,
   endAt,
diff --git a/packages/database/src/api/Reference_impl.ts b/packages/database/src/api/Reference_impl.ts
index eec1b1afafe..531c5d794da 100644
--- a/packages/database/src/api/Reference_impl.ts
+++ b/packages/database/src/api/Reference_impl.ts
@@ -376,7 +376,7 @@ export class DataSnapshot {
   }
 
   /**
-   * Enumerates the top-level children in the `DataSnapshot`.
+   * Enumerates the top-level children in the `IteratedDataSnapshot`.
    *
    * Because of the way JavaScript objects work, the ordering of data in the
    * JavaScript object returned by `val()` is not guaranteed to match the
@@ -393,7 +393,7 @@ export class DataSnapshot {
    * @returns true if enumeration was canceled due to your callback returning
    * true.
    */
-  forEach(action: (child: DataSnapshot) => boolean | void): boolean {
+  forEach(action: (child: IteratedDataSnapshot) => boolean | void): boolean {
     if (this._node.isLeafNode()) {
       return false;
     }
@@ -463,6 +463,13 @@ export class DataSnapshot {
   }
 }
 
+/**
+ * Represents a child snapshot of a `Reference` that is being iterated over. The key will never be undefined.
+ */
+export interface IteratedDataSnapshot extends DataSnapshot {
+  key: string; // key of the location of this snapshot.
+}
+
 /**
  *
  * Returns a `Reference` representing the location in the Database
diff --git a/packages/firebase/compat/index.d.ts b/packages/firebase/compat/index.d.ts
index f6ce4e5ea05..e4f62138d13 100644
--- a/packages/firebase/compat/index.d.ts
+++ b/packages/firebase/compat/index.d.ts
@@ -5819,7 +5819,7 @@ declare namespace firebase.database {
      *   returning true.
      */
     forEach(
-      action: (a: firebase.database.DataSnapshot) => boolean | void
+      action: (a: firebase.database.IteratorDataSnapshot) => boolean | void
     ): boolean;
     /**
      * Gets the priority value of the data in this `DataSnapshot`.