diff --git a/.changeset/eight-hats-laugh.md b/.changeset/eight-hats-laugh.md
new file mode 100644
index 00000000000..3b4de093348
--- /dev/null
+++ b/.changeset/eight-hats-laugh.md
@@ -0,0 +1,7 @@
+---
+'@primer/react': patch
+---
+
+perf(TreeView): Optimize typeahead with startTransition to prevent input lag
+
+Wrapped the expensive typeahead search operation in `startTransition` to mark it as low-priority, keeping keystroke handling responsive while deferring the focus search. This improves performance on large trees with thousands of items.
diff --git a/packages/react/src/TreeView/useTypeahead.ts b/packages/react/src/TreeView/useTypeahead.ts
index 128b6f967eb..8c3eb97f18c 100644
--- a/packages/react/src/TreeView/useTypeahead.ts
+++ b/packages/react/src/TreeView/useTypeahead.ts
@@ -1,4 +1,4 @@
-import React from 'react'
+import React, {startTransition} from 'react'
 import useSafeTimeout from '../hooks/useSafeTimeout'
 import {getAccessibleName} from './shared'
 import {useTreeItemCache} from './useTreeItemCache'
@@ -71,7 +71,10 @@ export function useTypeahead({containerRef, onFocusChange}: TypeaheadOptions) {
 
       // Update the existing search value with the new key press
       searchValue.current += event.key
-      focusSearchValue(searchValue.current)
+      // Defer the expensive search operation to avoid blocking user input
+      startTransition(() => {
+        focusSearchValue(searchValue.current)
+      })
 
       // Reset the timeout
       safeClearTimeout(timeoutRef.current)