diff --git a/bookwyrm/tests/activitypub/test_base_activity.py b/bookwyrm/tests/activitypub/test_base_activity.py
index a545beb3e..34a968426 100644
--- a/bookwyrm/tests/activitypub/test_base_activity.py
+++ b/bookwyrm/tests/activitypub/test_base_activity.py
@@ -46,6 +46,13 @@ class BaseActivity(TestCase):
         # don't try to load the user icon
         del self.userdata["icon"]
 
+        alias_datafile = pathlib.Path(__file__).parent.joinpath(
+            "../data/ap_user_aliased.json"
+        )
+        self.alias_userdata = json.loads(alias_datafile.read_bytes())
+        # don't try to load the user icon
+        del self.alias_userdata["icon"]
+
         image_path = pathlib.Path(__file__).parent.joinpath(
             "../../static/images/default_avi.jpg"
         )
@@ -110,6 +117,13 @@ class BaseActivity(TestCase):
             status=200,
         )
 
+        responses.add(
+            responses.GET,
+            "https://example.com/user/moose",
+            json=self.alias_userdata,
+            status=200,
+        )
+
         with patch("bookwyrm.models.user.set_remote_server.delay"):
             result = resolve_remote_id(
                 "https://example.com/user/mouse", model=models.User
@@ -118,6 +132,42 @@ class BaseActivity(TestCase):
         self.assertEqual(result.remote_id, "https://example.com/user/mouse")
         self.assertEqual(result.name, "MOUSE?? MOUSE!!")
 
+    @responses.activate
+    def test_resolve_remote_alias(self, *_):
+        """look up or load user who has an unknown alias"""
+
+        self.assertEqual(models.User.objects.count(), 1)
+
+        # remote user with unknown user as an alias
+        responses.add(
+            responses.GET,
+            "https://example.com/user/moose",
+            json=self.alias_userdata,
+            status=200,
+        )
+
+        responses.add(
+            responses.GET,
+            "https://example.com/user/mouse",
+            json=self.userdata,
+            status=200,
+        )
+
+        with patch("bookwyrm.models.user.set_remote_server.delay"):
+            result = resolve_remote_id(
+                "https://example.com/user/mouse", model=models.User
+            )
+        self.assertIsInstance(result, models.User)
+        self.assertEqual(result.name, "MOUSE?? MOUSE!!")
+        self.assertEqual(
+            models.User.objects.count(), 3
+        )  # created a new mouse plus the alias
+        alias = models.User.objects.last()  # moose
+        self.assertEqual(alias.name, "moose?? moose!!")  # check it's moose
+        self.assertEqual(
+            result.also_known_as.first(), alias
+        )  # moose is alias of new mouse
+
     def test_to_model_invalid_model(self, *_):
         """catch mismatch between activity type and model type"""
         instance = ActivityObject(id="a", type="b")
diff --git a/bookwyrm/tests/data/ap_user.json b/bookwyrm/tests/data/ap_user.json
index 63c8a7e83..b1d3f173c 100644
--- a/bookwyrm/tests/data/ap_user.json
+++ b/bookwyrm/tests/data/ap_user.json
@@ -28,6 +28,7 @@
     },
     "bookwyrmUser": true,
     "manuallyApprovesFollowers": false,
+    "alsoKnownAs": ["https://example.com/user/moose"],
     "discoverable": false,
     "devices": "https://friend.camp/users/tripofmice/collections/devices",
     "tag": [],
diff --git a/bookwyrm/tests/data/ap_user_aliased.json b/bookwyrm/tests/data/ap_user_aliased.json
new file mode 100644
index 000000000..aa027a647
--- /dev/null
+++ b/bookwyrm/tests/data/ap_user_aliased.json
@@ -0,0 +1,40 @@
+{
+    "@context": [
+        "https://www.w3.org/ns/activitystreams",
+        "https://w3id.org/security/v1",
+        {
+            "manuallyApprovesFollowers": "as:manuallyApprovesFollowers",
+            "schema": "http://schema.org#",
+            "PropertyValue": "schema:PropertyValue",
+            "value": "schema:value"
+        }
+    ],
+    "id": "https://example.com/user/moose",
+    "type": "Person",
+    "preferredUsername": "moose",
+    "name": "moose?? moose!!",
+    "inbox": "https://example.com/user/moose/inbox",
+    "outbox": "https://example.com/user/moose/outbox",
+    "followers": "https://example.com/user/moose/followers",
+    "following": "https://example.com/user/moose/following",
+    "summary": "",
+    "publicKey": {
+        "id": "https://example.com/user/moose/#main-key",
+        "owner": "https://example.com/user/moose",
+        "publicKeyPem": "-----BEGIN PUBLIC KEY-----\nMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC6QisDrjOQvkRo/MqNmSYPwqtt\nCxg/8rCW+9jKbFUKvqjTeKVotEE85122v/DCvobCCdfQuYIFdVMk+dB1xJ0iPGPg\nyU79QHY22NdV9mFKA2qtXVVxb5cxpA4PlwOHM6PM/k8B+H09OUrop2aPUAYwy+vg\n+MXyz8bAXrIS1kq6fQIDAQAB\n-----END PUBLIC KEY-----"
+    },
+    "endpoints": {
+        "sharedInbox": "https://example.com/inbox"
+    },
+    "bookwyrmUser": true,
+    "manuallyApprovesFollowers": false,
+    "discoverable": false,
+    "alsoKnownAs": ["http://example.com/a/b"],
+    "devices": "",
+    "tag": [],
+    "icon": {
+        "type": "Image",
+        "mediaType": "image/png",
+        "url": "https://example.com/images/avatars/AL-3-crop-50.png"
+    }
+}