diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index 87c1c9a..32cd8bb 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -991,11 +991,13 @@
 PyOS_AfterFork(void)
 {
 #ifdef WITH_THREAD
+    /* PyThread_ReInitTLS() must be called early, to make sure that the TLS API
+     * can be called safely. */
+    PyThread_ReInitTLS();
     _PyGILState_Reinit();
     PyEval_ReInitThreads();
     main_thread = PyThread_get_thread_ident();
     main_pid = getpid();
     _PyImport_ReInitLock();
-    PyThread_ReInitTLS();
 #endif
 }