diff --git a/Python/pystate.c b/Python/pystate.c
index 15761e7..8077a3e 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -532,6 +532,7 @@
         Py_FatalError("PyState_RemoveModule: Module index out of bounds.");
         return -1;
     }
+    Py_INCREF(Py_None);
     return PyList_SetItem(state->modules_by_index, index, Py_None);
 }