diff --git a/panoptes_client/set_member_subject.py b/panoptes_client/set_member_subject.py
index 298e52f..c7ab2db 100644
--- a/panoptes_client/set_member_subject.py
+++ b/panoptes_client/set_member_subject.py
@@ -4,7 +4,9 @@
 class SetMemberSubject(PanoptesObject):
     _api_slug = 'set_member_subjects'
     _link_slug = 'set_member_subjects'
-    _edit_attributes = ()
+    _edit_attributes = (
+        'priority',
+    )
 
 LinkResolver.register(SetMemberSubject)
 LinkResolver.register(SetMemberSubject, 'set_member_subject')
diff --git a/panoptes_client/subject.py b/panoptes_client/subject.py
index db15562..1a9f23b 100644
--- a/panoptes_client/subject.py
+++ b/panoptes_client/subject.py
@@ -1,4 +1,5 @@
 from panoptes_client.subject_workflow_status import SubjectWorkflowStatus
+from panoptes_client.set_member_subject import SetMemberSubject
 
 _OLD_STR_TYPES = (str,)
 try:
@@ -467,6 +468,38 @@ def save_attached_image(
                     upload_exec.shutdown(wait=True)
         return future_result
 
+    def update_priority(self, priority, subject_set_id=None):
+        """
+        Update the priority of this subject in the subject set.
+
+        If subject_set_id is not provided, the priority will be updated in all subject sets that this subject belongs to.
+
+        - **priority** is an integer value that represents the priority of the subject in the subject set.
+
+        Examples::
+
+            subject.update_priority(1)
+            subject.update_priority(2, subject_set_id=1234)
+        """
+
+        if self.id is None:
+            raise ObjectNotSavedException
+        
+        self.metadata['priority'] = priority
+        self.save()
+
+        if subject_set_id is not None:
+            subject_sets = [subject_set_id]
+        else:
+            subject_sets = [s.id for s in self.links.subject_sets]
+
+        for ss_id in subject_sets:
+            sms = next(SetMemberSubject.where(
+                subject_set_id=ss_id,
+                subject_id=self.id))
+            sms.priority = priority
+            sms.save()
+
 
 class UnknownMediaException(Exception):
     pass
diff --git a/panoptes_client/tests/test_subject.py b/panoptes_client/tests/test_subject.py
index 15b5e83..c1c1a8a 100644
--- a/panoptes_client/tests/test_subject.py
+++ b/panoptes_client/tests/test_subject.py
@@ -1,9 +1,10 @@
 import io
+import mimetypes
 import unittest
-from unittest.mock import patch, mock_open
+from unittest.mock import patch, mock_open, MagicMock
 
+from panoptes_client.panoptes import ObjectNotSavedException
 from panoptes_client.subject import Subject, UnknownMediaException
-import mimetypes
 
 
 class TestSubject(unittest.TestCase):
@@ -39,7 +40,7 @@ def test_add_location_magic_detection(self, mock_magic):
         self.assertIn("locations", self.subject.modified_attributes)
         mock_magic.from_buffer.assert_called_with(data, mime=True)
 
-    @patch.object(mimetypes, 'guess_type', return_value=("image/jpeg", None))
+    @patch("panoptes_client.subject.mimetypes.guess_type", return_value=("image/jpeg", None))
     def test_add_location_mimetypes_detection(self, mock_guess_type):
         import panoptes_client.subject as subject_module
         subject_module.MEDIA_TYPE_DETECTION = 'mimetypes'
@@ -56,4 +57,75 @@ def test_add_location_invalid_manual_mimetype(self):
         data = b"fake data"
         fake_file = io.BytesIO(data)
         with self.assertRaises(UnknownMediaException):
-            self.subject.add_location(fake_file, manual_mimetype="application/javascript")
\ No newline at end of file
+            self.subject.add_location(fake_file, manual_mimetype="application/javascript")
+
+    def test_update_priority_requires_saved_subject(self):
+        with self.assertRaises(ObjectNotSavedException):
+            self.subject.update_priority(1)
+
+    def test_update_priority_updates_priority_for_saved_subject(self):
+        self.subject.id = 123  
+        set_member_subject_mock = MagicMock()
+
+        with patch.object(self.subject, "save") as mock_save:
+            with patch(
+                "panoptes_client.subject.SetMemberSubject.where",
+                return_value=iter([set_member_subject_mock]),
+            ) as mock_where:
+                self.subject.update_priority(
+                    5,
+                    subject_set_id=456,
+                )
+
+        self.assertEqual(self.subject.metadata["priority"], 5)
+
+        mock_save.assert_called_once_with()
+        mock_where.assert_called_once_with(
+            subject_set_id=456,
+            subject_id=123,
+        )
+
+        self.assertEqual(set_member_subject_mock.priority, 5)
+        set_member_subject_mock.save.assert_called_once_with()
+
+    def test_update_priority_updates_all_subject_sets(self):
+        self.subject.id = 123
+
+        subject_set_1 = MagicMock(id=456)
+        subject_set_2 = MagicMock(id=789)
+        set_member_subject_1 = MagicMock()
+        set_member_subject_2 = MagicMock()
+
+        with patch.object(self.subject, "save") as mock_save, \
+            patch(
+             "panoptes_client.panoptes.LinkResolver.__getattr__",
+             return_value=[subject_set_1, subject_set_2],
+            ),  \
+            patch(
+                "panoptes_client.subject.SetMemberSubject.where",
+                side_effect=[
+                    iter([set_member_subject_1]),
+                    iter([set_member_subject_2]),
+                ],
+            ) as mock_where:
+            self.subject.update_priority(5)
+
+        self.assertEqual(self.subject.metadata["priority"], 5)
+
+        mock_save.assert_called_once_with()
+
+        self.assertEqual(mock_where.call_count, 2)
+        mock_where.assert_any_call(
+            subject_set_id=456,
+            subject_id=123,
+        )
+        mock_where.assert_any_call(
+            subject_set_id=789,
+            subject_id=123,
+        )
+
+        self.assertEqual(set_member_subject_1.priority, 5)
+        set_member_subject_1.save.assert_called_once_with()
+
+        self.assertEqual(set_member_subject_2.priority, 5)
+        set_member_subject_2.save.assert_called_once_with()