diff --git a/packages/react-server-dom-esm/src/ReactFlightESMReferences.js b/packages/react-server-dom-esm/src/ReactFlightESMReferences.js
index 2b051e72f987d..9a3346c4bf280 100644
--- a/packages/react-server-dom-esm/src/ReactFlightESMReferences.js
+++ b/packages/react-server-dom-esm/src/ReactFlightESMReferences.js
@@ -63,8 +63,8 @@ function bind(this: ServerReference<any>): any {
   return newFn;
 }
 
-export function registerServerReference<T>(
-  reference: ServerReference<T>,
+export function registerServerReference<T: Function>(
+  reference: T,
   id: string,
   exportName: string,
 ): ServerReference<T> {
diff --git a/packages/react-server-dom-turbopack/src/ReactFlightTurbopackReferences.js b/packages/react-server-dom-turbopack/src/ReactFlightTurbopackReferences.js
index 39b178ed9f561..89985348b2c78 100644
--- a/packages/react-server-dom-turbopack/src/ReactFlightTurbopackReferences.js
+++ b/packages/react-server-dom-turbopack/src/ReactFlightTurbopackReferences.js
@@ -76,8 +76,8 @@ function bind(this: ServerReference<any>): any {
   return newFn;
 }
 
-export function registerServerReference<T>(
-  reference: ServerReference<T>,
+export function registerServerReference<T: Function>(
+  reference: T,
   id: string,
   exportName: null | string,
 ): ServerReference<T> {
diff --git a/packages/react-server-dom-webpack/src/ReactFlightWebpackReferences.js b/packages/react-server-dom-webpack/src/ReactFlightWebpackReferences.js
index 059925a3cfa1a..b174953a72c4f 100644
--- a/packages/react-server-dom-webpack/src/ReactFlightWebpackReferences.js
+++ b/packages/react-server-dom-webpack/src/ReactFlightWebpackReferences.js
@@ -76,8 +76,8 @@ function bind(this: ServerReference<any>): any {
   return newFn;
 }
 
-export function registerServerReference<T>(
-  reference: ServerReference<T>,
+export function registerServerReference<T: Function>(
+  reference: T,
   id: string,
   exportName: null | string,
 ): ServerReference<T> {