diff --git a/app/repositories/users.py b/app/repositories/users.py
index c0c71c5..0fa5998 100644
--- a/app/repositories/users.py
+++ b/app/repositories/users.py
@@ -19,13 +19,11 @@ def add_user(username: str) -> User:
     return user
 
 
-def edit_user(user_id: str, data) -> User:
+def edit_user(user_id: str, data: dict) -> User:
     user = get_user_by_id(user_id)
 
-    if title := data.get("title"):
-        user.title = title
-    if is_done := data.get("is_done"):
-        user.is_done = is_done
+    if username := data.get("username"):
+        user.username = username
 
     return user
 
diff --git a/app/schema/mutations/__init__.py b/app/schema/mutations/__init__.py
index ad133b0..2ca81d4 100644
--- a/app/schema/mutations/__init__.py
+++ b/app/schema/mutations/__init__.py
@@ -3,3 +3,4 @@ from .create_todo import CreateTodo
 from .delete_todo import DeleteTodo
 from .update_todo import UpdateTodo
 from .create_user import CreateUser
+from .update_user import UpdateUser
diff --git a/app/schema/mutations/mutations.py b/app/schema/mutations/mutations.py
index 8b93b4c..47880fe 100644
--- a/app/schema/mutations/mutations.py
+++ b/app/schema/mutations/mutations.py
@@ -1,6 +1,6 @@
 import graphene
 
-from . import CreateTodo, DeleteTodo, UpdateTodo, CloseTodo, CreateUser
+from . import CreateTodo, DeleteTodo, UpdateTodo, CloseTodo, CreateUser, UpdateUser
 
 
 class Mutations(graphene.ObjectType):
@@ -11,3 +11,4 @@ class Mutations(graphene.ObjectType):
     close_todo = CloseTodo.Field()
     # user
     create_user = CreateUser.Field()
+    update_user = UpdateUser.Field()
diff --git a/app/schema/mutations/update_user.py b/app/schema/mutations/update_user.py
new file mode 100644
index 0000000..837ed37
--- /dev/null
+++ b/app/schema/mutations/update_user.py
@@ -0,0 +1,21 @@
+import graphene
+
+from app.models.user import User
+from app.schema.types.user import UserInputType, UserResponseField
+from app.usecases.user.update_user import update_user
+
+
+class UpdateUser(graphene.Mutation):
+    class Arguments:
+        user = UserInputType()
+
+    result = graphene.Field(UserResponseField)
+
+    def mutate(self, info, user: User):
+        res, is_success = update_user(user.user_id, vars(user))
+        error_message = "This user does not exist." if not is_success else None
+        return UpdateUser(
+            UserResponseField(
+                user=res, is_success=is_success, error_message=error_message
+            )
+        )
diff --git a/app/schema/types/user.py b/app/schema/types/user.py
index 43c2e1b..736dd17 100644
--- a/app/schema/types/user.py
+++ b/app/schema/types/user.py
@@ -8,6 +8,11 @@ class UserType(graphene.ObjectType):
     username = graphene.String()
 
 
+class UserInputType(graphene.InputObjectType):
+    user_id = graphene.String()
+    username = graphene.String()
+
+
 class UserListResponseField(ResponseField):
     users = graphene.List(UserType)
 
diff --git a/app/usecases/user/update_user.py b/app/usecases/user/update_user.py
new file mode 100644
index 0000000..242ff7c
--- /dev/null
+++ b/app/usecases/user/update_user.py
@@ -0,0 +1,11 @@
+from typing import Tuple
+
+from app.models.user import User
+from app.repositories.users import user_exists, edit_user
+
+
+def update_user(user_id: str, data: dict) -> Tuple[User, bool]:
+    if not user_exists(user_id=user_id):
+        return None, False
+
+    return edit_user(user_id, data), True