diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 2afd5a60973..b8d0021931b 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -6194,7 +6194,7 @@ posix_unsetenv(PyObject *self, PyObject *args)
 
     err = unsetenv(s1);
     if (err) {
-        Py_DECREF(s1);
+        Py_DECREF(os1);
         return posix_error();
     }