diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 1f3b50187..1c6b22e53 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -4,6 +4,11 @@ Change history for XBlock
 
 These are notable changes in XBlock.
 
+1.5.1 - 2021-08-26
+------------------
+
+* Deprecated the Runtime.user_id property in favor of the user service.
+
 1.5.0 - 2021-07-27
 ------------------
 
diff --git a/xblock/VERSION.txt b/xblock/VERSION.txt
index bc80560fa..26ca59460 100644
--- a/xblock/VERSION.txt
+++ b/xblock/VERSION.txt
@@ -1 +1 @@
-1.5.0
+1.5.1
diff --git a/xblock/exceptions.py b/xblock/exceptions.py
index 9e58a62ec..04694c0aa 100644
--- a/xblock/exceptions.py
+++ b/xblock/exceptions.py
@@ -138,6 +138,10 @@ class FieldDataDeprecationWarning(DeprecationWarning):
     """Warning for use of deprecated _field_data accessor"""
 
 
+class UserIdDeprecationWarning(DeprecationWarning):
+    """Warning for use of deprecated user_id accessor"""
+
+
 class XBlockParseException(Exception):
     """
     Raised if parsing the XBlock olx fails.
diff --git a/xblock/runtime.py b/xblock/runtime.py
index 8bad3a85e..c518eda5a 100644
--- a/xblock/runtime.py
+++ b/xblock/runtime.py
@@ -29,6 +29,7 @@
     NoSuchUsage,
     NoSuchDefinition,
     FieldDataDeprecationWarning,
+    UserIdDeprecationWarning,
 )
 
 log = logging.getLogger(__name__)
@@ -563,7 +564,7 @@ def __init__(
         self.default_class = default_class
         self.select = select
 
-        self.user_id = None
+        self._deprecated_per_instance_user_id = None  # pylint: disable=invalid-name
         self.mixologist = Mixologist(mixins)
         self._view_name = None
 
@@ -593,6 +594,26 @@ def field_data(self, field_data):
         warnings.warn("Runtime.field_data is deprecated", FieldDataDeprecationWarning, stacklevel=2)
         self._deprecated_per_instance_field_data = field_data
 
+    @property
+    def user_id(self):
+        """
+        Access the current user ID.
+
+        Deprecated in favor of a 'user' service.
+        """
+        warnings.warn("Runtime.user_id is deprecated", UserIdDeprecationWarning, stacklevel=2)
+        return self._deprecated_per_instance_user_id
+
+    @user_id.setter
+    def user_id(self, user_id):
+        """
+        Set the current user ID.
+
+        Deprecated in favor of a 'user' service.
+        """
+        warnings.warn("Runtime.user_id is deprecated", UserIdDeprecationWarning, stacklevel=2)
+        self._deprecated_per_instance_user_id = user_id
+
     def load_block_type(self, block_type):
         """
         Returns a subclass of :class:`.XBlock` that corresponds to the specified `block_type`.