diff --git a/backend/__tests__/api/controllers/user.spec.ts b/backend/__tests__/api/controllers/user.spec.ts
index 746d8696f..d6164eeb6 100644
--- a/backend/__tests__/api/controllers/user.spec.ts
+++ b/backend/__tests__/api/controllers/user.spec.ts
@@ -783,6 +783,7 @@ describe("user controller test", () => {
     });
   });
   describe("update name", () => {
+    const blocklistContainsMock = vi.spyOn(BlocklistDal, "contains");
     const getPartialUserMock = vi.spyOn(UserDal, "getPartialUser");
     const updateNameMock = vi.spyOn(UserDal, "updateName");
     const addImportantLogMock = vi.spyOn(LogDal, "addImportantLog");
@@ -791,6 +792,7 @@ describe("user controller test", () => {
       getPartialUserMock.mockReset();
       updateNameMock.mockReset();
       addImportantLogMock.mockReset();
+      blocklistContainsMock.mockReset();
     });
 
     it("should update the username", async () => {
@@ -819,6 +821,23 @@ describe("user controller test", () => {
         uid
       );
     });
+
+    it("should fail if username is blocked", async () => {
+      //GIVEN
+      blocklistContainsMock.mockResolvedValue(true);
+
+      //WHEN
+      const { body } = await mockApp
+        .patch("/users/name")
+        .set("authorization", `Uid ${uid}`)
+        .send({ name: "newName" })
+        .expect(409);
+
+      //THEN
+      expect(body.message).toEqual("Username blocked");
+      expect(updateNameMock).not.toHaveBeenCalled();
+    });
+
     it("should fail for banned users", async () => {
       //GIVEN
       getPartialUserMock.mockResolvedValue({ banned: true } as any);
diff --git a/backend/src/api/controllers/user.ts b/backend/src/api/controllers/user.ts
index 755ec52fe..366d0d584 100644
--- a/backend/src/api/controllers/user.ts
+++ b/backend/src/api/controllers/user.ts
@@ -326,6 +326,11 @@ export async function updateName(
   const { uid } = req.ctx.decodedToken;
   const { name } = req.body;
 
+  const blocklisted = await BlocklistDal.contains({ name });
+  if (blocklisted) {
+    throw new MonkeyError(409, "Username blocked");
+  }
+
   const user = await UserDAL.getPartialUser(uid, "update name", [
     "name",
     "banned",