diff --git a/.changeset/hot-hotels-tie.md b/.changeset/hot-hotels-tie.md
new file mode 100644
index 00000000000..2cf3f676b8b
--- /dev/null
+++ b/.changeset/hot-hotels-tie.md
@@ -0,0 +1,5 @@
+---
+'@keystone-next/keystone': patch
+---
+
+Fixed Admin UI generation to allow files returned from `getAdditionalFiles` to overwrite the files generated by Keystone
diff --git a/packages-next/keystone/src/admin-ui/system/generateAdminUI.ts b/packages-next/keystone/src/admin-ui/system/generateAdminUI.ts
index d9bfd4b2440..250a48e1249 100644
--- a/packages-next/keystone/src/admin-ui/system/generateAdminUI.ts
+++ b/packages-next/keystone/src/admin-ui/system/generateAdminUI.ts
@@ -89,7 +89,7 @@ export const generateAdminUI = async (
   );
   await Promise.all(
     adminFiles
-      .filter(x => !uniqueFiles.has(Path.normalize(x.outputPath)))
+      .filter(x => !uniqueFiles.has(Path.normalize(Path.join(projectAdminPath, x.outputPath))))
       .map(file => writeAdminFile(file, projectAdminPath))
   );