diff --git a/Misc/NEWS.d/next/Build/2025-02-02-09-11-45.gh-issue-129539.SYXXCg.rst b/Misc/NEWS.d/next/Build/2025-02-02-09-11-45.gh-issue-129539.SYXXCg.rst
new file mode 100644
index 00000000000000..9781dc05b64823
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2025-02-02-09-11-45.gh-issue-129539.SYXXCg.rst
@@ -0,0 +1 @@
+Don't redefine ``EX_OK`` when the system has the ``sysexits.h`` header.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index c386f15b1714e1..c21c6f06c729de 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -49,10 +49,6 @@
 #  include "winreparse.h"
 #endif
 
-#if !defined(EX_OK) && defined(EXIT_SUCCESS)
-#  define EX_OK EXIT_SUCCESS
-#endif
-
 /* On android API level 21, 'AT_EACCESS' is not declared although
  * HAVE_FACCESSAT is defined. */
 #ifdef __ANDROID__
@@ -270,6 +266,10 @@ corresponding Unix manual entries for more information on calls.");
 #  include <sysexits.h>
 #endif
 
+#if !defined(EX_OK) && defined(EXIT_SUCCESS)
+#  define EX_OK EXIT_SUCCESS
+#endif
+
 #ifdef HAVE_SYS_LOADAVG_H
 #  include <sys/loadavg.h>
 #endif