diff --git a/changelog.d/11524.bugfix b/changelog.d/11524.bugfix
new file mode 100644
index 000000000000..6e1e4bd44c3c
--- /dev/null
+++ b/changelog.d/11524.bugfix
@@ -0,0 +1 @@
+Fix a regression in Synapse 1.48.0 where the module API's `looping_background_call` method would spam errors to the logs when given a non-async function.
diff --git a/synapse/module_api/__init__.py b/synapse/module_api/__init__.py
index 6bfb4b8d1be1..662e60bc3394 100644
--- a/synapse/module_api/__init__.py
+++ b/synapse/module_api/__init__.py
@@ -108,6 +108,7 @@
     create_requester,
 )
 from synapse.util import Clock
+from synapse.util.async_helpers import maybe_awaitable
 from synapse.util.caches.descriptors import cached
 
 if TYPE_CHECKING:
@@ -1014,9 +1015,7 @@ def looping_background_call(
                 run_as_background_process,
                 msec,
                 desc,
-                f,
-                *args,
-                **kwargs,
+                lambda: maybe_awaitable(f(*args, **kwargs)),
             )
         else:
             logger.warning(