diff --git a/packages/react-is/src/ReactIs.js b/packages/react-is/src/ReactIs.js
index db7552976f37d..a433e91bf1064 100644
--- a/packages/react-is/src/ReactIs.js
+++ b/packages/react-is/src/ReactIs.js
@@ -24,9 +24,20 @@ import {
   REACT_SUSPENSE_TYPE,
   REACT_SUSPENSE_LIST_TYPE,
   REACT_VIEW_TRANSITION_TYPE,
+  REACT_SCOPE_TYPE,
+  REACT_LEGACY_HIDDEN_TYPE,
+  REACT_TRACING_MARKER_TYPE,
 } from 'shared/ReactSymbols';
-import isValidElementType from 'shared/isValidElementType';
-import {enableRenderableContext} from 'shared/ReactFeatureFlags';
+
+import {
+  enableRenderableContext,
+  enableScopeAPI,
+  enableTransitionTracing,
+  enableLegacyHidden,
+  enableViewTransition,
+} from 'shared/ReactFeatureFlags';
+
+const REACT_CLIENT_REFERENCE: symbol = Symbol.for('react.client.reference');
 
 export function typeOf(object: any): mixed {
   if (typeof object === 'object' && object !== null) {
@@ -91,7 +102,47 @@ export const StrictMode = REACT_STRICT_MODE_TYPE;
 export const Suspense = REACT_SUSPENSE_TYPE;
 export const SuspenseList = REACT_SUSPENSE_LIST_TYPE;
 
-export {isValidElementType};
+export function isValidElementType(type: mixed): boolean {
+  if (typeof type === 'string' || typeof type === 'function') {
+    return true;
+  }
+
+  // Note: typeof might be other than 'symbol' or 'number' (e.g. if it's a polyfill).
+  if (
+    type === REACT_FRAGMENT_TYPE ||
+    type === REACT_PROFILER_TYPE ||
+    type === REACT_STRICT_MODE_TYPE ||
+    type === REACT_SUSPENSE_TYPE ||
+    type === REACT_SUSPENSE_LIST_TYPE ||
+    (enableLegacyHidden && type === REACT_LEGACY_HIDDEN_TYPE) ||
+    (enableScopeAPI && type === REACT_SCOPE_TYPE) ||
+    (enableTransitionTracing && type === REACT_TRACING_MARKER_TYPE) ||
+    (enableViewTransition && type === REACT_VIEW_TRANSITION_TYPE)
+  ) {
+    return true;
+  }
+
+  if (typeof type === 'object' && type !== null) {
+    if (
+      type.$$typeof === REACT_LAZY_TYPE ||
+      type.$$typeof === REACT_MEMO_TYPE ||
+      type.$$typeof === REACT_CONTEXT_TYPE ||
+      (!enableRenderableContext && type.$$typeof === REACT_PROVIDER_TYPE) ||
+      (enableRenderableContext && type.$$typeof === REACT_CONSUMER_TYPE) ||
+      type.$$typeof === REACT_FORWARD_REF_TYPE ||
+      // This needs to include all possible module reference object
+      // types supported by any Flight configuration anywhere since
+      // we don't know which Flight build this will end up being used
+      // with.
+      type.$$typeof === REACT_CLIENT_REFERENCE ||
+      type.getModuleId !== undefined
+    ) {
+      return true;
+    }
+  }
+
+  return false;
+}
 
 export function isContextConsumer(object: any): boolean {
   if (enableRenderableContext) {
diff --git a/packages/react/src/ReactMemo.js b/packages/react/src/ReactMemo.js
index 0149712b054c5..8f2c0f53827c9 100644
--- a/packages/react/src/ReactMemo.js
+++ b/packages/react/src/ReactMemo.js
@@ -9,14 +9,12 @@
 
 import {REACT_MEMO_TYPE} from 'shared/ReactSymbols';
 
-import isValidElementType from 'shared/isValidElementType';
-
 export function memo<Props>(
   type: React$ElementType,
   compare?: (oldProps: Props, newProps: Props) => boolean,
 ) {
   if (__DEV__) {
-    if (!isValidElementType(type)) {
+    if (type == null) {
       console.error(
         'memo: The first argument must be a component. Instead ' +
           'received: %s',
diff --git a/packages/shared/isValidElementType.js b/packages/shared/isValidElementType.js
deleted file mode 100644
index 84e4fe802a930..0000000000000
--- a/packages/shared/isValidElementType.js
+++ /dev/null
@@ -1,81 +0,0 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
- * @flow
- */
-
-import {
-  REACT_CONTEXT_TYPE,
-  REACT_CONSUMER_TYPE,
-  REACT_PROVIDER_TYPE,
-  REACT_FORWARD_REF_TYPE,
-  REACT_FRAGMENT_TYPE,
-  REACT_PROFILER_TYPE,
-  REACT_STRICT_MODE_TYPE,
-  REACT_SUSPENSE_TYPE,
-  REACT_SUSPENSE_LIST_TYPE,
-  REACT_MEMO_TYPE,
-  REACT_LAZY_TYPE,
-  REACT_SCOPE_TYPE,
-  REACT_LEGACY_HIDDEN_TYPE,
-  REACT_TRACING_MARKER_TYPE,
-  REACT_VIEW_TRANSITION_TYPE,
-  REACT_ACTIVITY_TYPE,
-} from 'shared/ReactSymbols';
-import {
-  enableScopeAPI,
-  enableTransitionTracing,
-  enableLegacyHidden,
-  enableRenderableContext,
-  enableViewTransition,
-} from './ReactFeatureFlags';
-
-const REACT_CLIENT_REFERENCE: symbol = Symbol.for('react.client.reference');
-
-// This function is deprecated. Don't use. Only the renderer knows what a valid type is.
-// TODO: Delete this now that owner stacks shipped.
-export default function isValidElementType(type: mixed): boolean {
-  if (typeof type === 'string' || typeof type === 'function') {
-    return true;
-  }
-
-  // Note: typeof might be other than 'symbol' or 'number' (e.g. if it's a polyfill).
-  if (
-    type === REACT_FRAGMENT_TYPE ||
-    type === REACT_PROFILER_TYPE ||
-    type === REACT_STRICT_MODE_TYPE ||
-    type === REACT_SUSPENSE_TYPE ||
-    type === REACT_SUSPENSE_LIST_TYPE ||
-    (enableLegacyHidden && type === REACT_LEGACY_HIDDEN_TYPE) ||
-    type === REACT_ACTIVITY_TYPE ||
-    (enableScopeAPI && type === REACT_SCOPE_TYPE) ||
-    (enableTransitionTracing && type === REACT_TRACING_MARKER_TYPE) ||
-    (enableViewTransition && type === REACT_VIEW_TRANSITION_TYPE)
-  ) {
-    return true;
-  }
-
-  if (typeof type === 'object' && type !== null) {
-    if (
-      type.$$typeof === REACT_LAZY_TYPE ||
-      type.$$typeof === REACT_MEMO_TYPE ||
-      type.$$typeof === REACT_CONTEXT_TYPE ||
-      (!enableRenderableContext && type.$$typeof === REACT_PROVIDER_TYPE) ||
-      (enableRenderableContext && type.$$typeof === REACT_CONSUMER_TYPE) ||
-      type.$$typeof === REACT_FORWARD_REF_TYPE ||
-      // This needs to include all possible module reference object
-      // types supported by any Flight configuration anywhere since
-      // we don't know which Flight build this will end up being used
-      // with.
-      type.$$typeof === REACT_CLIENT_REFERENCE ||
-      type.getModuleId !== undefined
-    ) {
-      return true;
-    }
-  }
-
-  return false;
-}