diff --git a/Include/internal/mimalloc/mimalloc/prim.h b/Include/internal/mimalloc/mimalloc/prim.h
index 4b9e4dc4194..8a60d528458 100644
--- a/Include/internal/mimalloc/mimalloc/prim.h
+++ b/Include/internal/mimalloc/mimalloc/prim.h
@@ -131,7 +131,13 @@ extern bool _mi_process_is_initialized;             // has mi_process_init been
 
 static inline mi_threadid_t _mi_prim_thread_id(void) mi_attr_noexcept;
 
-#if defined(_WIN32)
+#ifdef MI_PRIM_THREAD_ID
+
+static inline mi_threadid_t _mi_prim_thread_id(void) mi_attr_noexcept {
+  return MI_PRIM_THREAD_ID();
+}
+
+#elif defined(_WIN32)
 
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
diff --git a/Include/internal/pycore_mimalloc.h b/Include/internal/pycore_mimalloc.h
index 1e7ed5a4ca6..14c98108ec1 100644
--- a/Include/internal/pycore_mimalloc.h
+++ b/Include/internal/pycore_mimalloc.h
@@ -20,9 +20,12 @@ typedef enum {
 #include "pycore_pymem.h"
 
 #ifdef WITH_MIMALLOC
-#define MI_DEBUG_UNINIT     PYMEM_CLEANBYTE
-#define MI_DEBUG_FREED      PYMEM_DEADBYTE
-#define MI_DEBUG_PADDING    PYMEM_FORBIDDENBYTE
+#  ifdef Py_GIL_DISABLED
+#    define MI_PRIM_THREAD_ID   _Py_ThreadId
+#  endif
+#  define MI_DEBUG_UNINIT     PYMEM_CLEANBYTE
+#  define MI_DEBUG_FREED      PYMEM_DEADBYTE
+#  define MI_DEBUG_PADDING    PYMEM_FORBIDDENBYTE
 #ifdef Py_DEBUG
 #  define MI_DEBUG 1
 #else