diff --git a/MIGRATION_GUIDE.md b/MIGRATION_GUIDE.md
index 7936fa52bf..04a9a3d4e5 100644
--- a/MIGRATION_GUIDE.md
+++ b/MIGRATION_GUIDE.md
@@ -8,6 +8,7 @@ Looking to upgrade from Sentry SDK 1.x to 2.x? Here's a comprehensive list of wh
 
 ## Changed
 
+- Subsequent calls to `sentry_sdk.set_user` will now update existing user data instead of overwriting it. To reset user data, call the function with an empty dictionary: `sentry_sdk.set_user({})`
 - The `BackgroundWorker` thread used to process events was renamed from `raven-sentry.BackgroundWorker` to `sentry-sdk.BackgroundWorker`.
 - The `reraise` function was moved from `sentry_sdk._compat` to `sentry_sdk.utils`.
 - Moved the contents of `tracing_utils_py3.py` to `tracing_utils.py`. The `start_child_span_decorator` is now in `sentry_sdk.tracing_utils`.
diff --git a/sentry_sdk/scope.py b/sentry_sdk/scope.py
index f1ce6890e5..c5d6019111 100644
--- a/sentry_sdk/scope.py
+++ b/sentry_sdk/scope.py
@@ -518,7 +518,12 @@ def user(self, value):
     def set_user(self, value):
         # type: (Optional[Dict[str, Any]]) -> None
         """Sets a user for the scope."""
-        self._user = value
+        if value:
+            self._user = self._user or {}
+            self._user.update(value)
+        else:
+            self._user = None
+
         if self._session is not None:
             self._session.update(user=value)
 
diff --git a/tests/test_scope.py b/tests/test_scope.py
index 88022e3920..dfa5fc2fa0 100644
--- a/tests/test_scope.py
+++ b/tests/test_scope.py
@@ -154,3 +154,41 @@ def test_load_trace_data_from_env(env, excepted_value):
         s = Scope()
         incoming_trace_data = s._load_trace_data_from_env()
         assert incoming_trace_data == excepted_value
+
+
+def test_user_update(sentry_init, capture_events):
+    sentry_init()
+    events = capture_events()
+
+    scope = Scope()
+    assert scope._user is None
+
+    scope.set_user({"id": 23})
+    assert scope._user == {"id": 23}
+
+    scope.set_user({"email": "lucy@dogs.com"})
+    assert scope._user == {"id": 23, "email": "lucy@dogs.com"}
+
+    capture_exception(NameError(), scope=scope)
+
+    (event,) = events
+    assert event["user"] == {"id": 23, "email": "lucy@dogs.com"}
+
+
+def test_user_reset(sentry_init, capture_events):
+    sentry_init()
+    events = capture_events()
+
+    scope = Scope()
+    assert scope._user is None
+
+    scope.set_user({"id": 23, "email": "dottie@dogs.com"})
+    assert scope._user == {"id": 23, "email": "dottie@dogs.com"}
+
+    scope.set_user({})
+    assert scope._user is None
+
+    capture_exception(NameError(), scope=scope)
+
+    (event,) = events
+    assert "user" not in event