diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -1121,6 +1121,9 @@
     return TRUE;
 }
 
+/* Note: We yielded the GIL in posix_do_stat. Must acquire before calling any
+   Python API functions in the following stat impls. */
+
 static int
 win32_xstat_impl_w(const wchar_t *path, struct win32_stat *result,
                    BOOL traverse);
@@ -1138,8 +1141,10 @@
     if(!check_GetFinalPathNameByHandle()) {
         /* If the OS doesn't have GetFinalPathNameByHandle, return a
            NotImplementedError. */
+        PyGILState_STATE state = PyGILState_Ensure();
         PyErr_SetString(PyExc_NotImplementedError,
             "GetFinalPathNameByHandle not available on this platform");
+        PyGILState_Release(state);
         return -1;
     }
 
@@ -1236,8 +1241,10 @@
     if(!check_GetFinalPathNameByHandle()) {
         /* If the OS doesn't have GetFinalPathNameByHandle, return a
            NotImplementedError. */
+        PyGILState_STATE state = PyGILState_Ensure();
         PyErr_SetString(PyExc_NotImplementedError,
             "GetFinalPathNameByHandle not available on this platform");
+        PyGILState_Release(state);
         return -1;
     }