diff --git a/.changeset/major-parks-study.md b/.changeset/major-parks-study.md
new file mode 100644
index 00000000000..55bf83977a6
--- /dev/null
+++ b/.changeset/major-parks-study.md
@@ -0,0 +1,5 @@
+---
+"@clerk/clerk-js": patch
+---
+
+Support both `clerkUICtor` and `clerkUiCtor` option names for backwards compatibility
diff --git a/packages/clerk-js/src/core/clerk.ts b/packages/clerk-js/src/core/clerk.ts
index 01395bac1b4..52ad8d2a7df 100644
--- a/packages/clerk-js/src/core/clerk.ts
+++ b/packages/clerk-js/src/core/clerk.ts
@@ -3248,9 +3248,14 @@ export class Clerk implements ClerkInterface {
   };
 
   #initOptions = (options?: ClerkOptions): ClerkOptions => {
+    // Support both clerkUICtor (correct) and clerkUiCtor (legacy) for backwards compatibility
+    const clerkUICtor =
+      options?.clerkUICtor ?? (options as Record<string, unknown> | undefined)?.clerkUiCtor ?? undefined;
+
     return {
       ...defaultOptions,
       ...options,
+      clerkUICtor: clerkUICtor as ClerkOptions['clerkUICtor'],
       allowedRedirectOrigins: createAllowedRedirectOrigins(
         options?.allowedRedirectOrigins,
         this.frontendApi,