diff --git a/Include/cpython/pyatomic_msc.h b/Include/cpython/pyatomic_msc.h
index 58dfdaaaf315ec..cf86c59cca9366 100644
--- a/Include/cpython/pyatomic_msc.h
+++ b/Include/cpython/pyatomic_msc.h
@@ -1083,8 +1083,8 @@ _Py_atomic_store_long_release(long *obj, long value)
 #if defined(_M_X64) || defined(_M_IX86)
     *(long volatile *)obj = value;
 #elif defined(_M_ARM64)
-    _Py_atomic_ASSERT_ARG_TYPE(unsigned __int64);
-    __stlr64((unsigned __int64 volatile *)obj, (unsigned __int64)value);
+    _Py_atomic_ASSERT_ARG_TYPE(unsigned __int32);
+    __stlr32((unsigned __int32 volatile *)obj, (unsigned __int32)value);
 #else
 #  error "no implementation of _Py_atomic_store_long_release"
 #endif