diff --git a/.changeset/sync-external-store-default.md b/.changeset/sync-external-store-default.md
new file mode 100644
index 0000000..5c92d6a
--- /dev/null
+++ b/.changeset/sync-external-store-default.md
@@ -0,0 +1,5 @@
+---
+'@tanstack/redact': patch
+---
+
+Put `useSyncExternalStoreWithSelector` on the default export. The Vite plugin aliases `use-sync-external-store/shim/with-selector` here, and zustand reads it as a CJS default import (`import shim from '...'; const { useSyncExternalStoreWithSelector } = shim`), so anything built on zustand's `useStoreWithEqualityFn` — React Flow, for one — threw `useSyncExternalStoreWithSelector is not a function`.
diff --git a/packages/redact/src/react/index.ts b/packages/redact/src/react/index.ts
index 9c07bbb..945d70e 100644
--- a/packages/redact/src/react/index.ts
+++ b/packages/redact/src/react/index.ts
@@ -104,6 +104,7 @@ import {
   useTransition,
   useDeferredValue,
   useSyncExternalStore,
+  useSyncExternalStoreWithSelector,
   use,
   useActionState,
   useFormStatus,
@@ -141,6 +142,9 @@ export default {
   useTransition,
   useDeferredValue,
   useSyncExternalStore,
+  // `use-sync-external-store/shim/with-selector` aliases here, and zustand
+  // reads it as a CJS default import.
+  useSyncExternalStoreWithSelector,
   use,
   useActionState,
   useFormStatus,
diff --git a/tests/default-export-shim.test.tsx b/tests/default-export-shim.test.tsx
new file mode 100644
index 0000000..047eb07
--- /dev/null
+++ b/tests/default-export-shim.test.tsx
@@ -0,0 +1,68 @@
+import { afterEach, describe, expect, it } from 'vitest'
+import React from 'react'
+import { createRoot } from 'react-dom/client'
+import { flushSync } from 'react-dom'
+
+// zustand reads the aliased `use-sync-external-store` shims as CJS default
+// imports, so the helpers have to be on the default export too.
+const { useSyncExternalStore, useSyncExternalStoreWithSelector } = React
+
+const cleanups: Array<() => void> = []
+afterEach(() => {
+  for (const cleanup of cleanups.splice(0)) cleanup()
+})
+
+function createStore<T>(initial: T) {
+  let state = initial
+  const listeners = new Set<() => void>()
+  return {
+    getState: () => state,
+    setState(next: T) {
+      state = next
+      for (const listener of listeners) listener()
+    },
+    subscribe(listener: () => void) {
+      listeners.add(listener)
+      return () => listeners.delete(listener)
+    },
+  }
+}
+
+describe('external store helpers on the default export', () => {
+  it('exposes both shim entry points', () => {
+    expect(typeof useSyncExternalStore).toBe('function')
+    expect(typeof useSyncExternalStoreWithSelector).toBe('function')
+  })
+
+  it('renders and updates through the selector helper', () => {
+    const store = createStore({ count: 0, other: 'x' })
+    const container = document.createElement('div')
+    const root = createRoot(container)
+    cleanups.push(() => {
+      flushSync(() => root.unmount())
+    })
+
+    let renders = 0
+    function Counter() {
+      renders += 1
+      const count = useSyncExternalStoreWithSelector(
+        store.subscribe,
+        store.getState,
+        store.getState,
+        (state) => state.count,
+      )
+      return <span>{count}</span>
+    }
+
+    flushSync(() => root.render(<Counter />))
+    expect(container.textContent).toBe('0')
+
+    flushSync(() => store.setState({ count: 1, other: 'x' }))
+    expect(container.textContent).toBe('1')
+
+    const before = renders
+    flushSync(() => store.setState({ count: 1, other: 'y' }))
+    expect(container.textContent).toBe('1')
+    expect(renders).toBe(before)
+  })
+})