diff --git a/Modules/timemodule.c b/Modules/timemodule.c
index 44cb9c8..5ff8eb3 100644
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -499,7 +499,9 @@ time_strftime(PyObject *self, PyObject *args)
 		if (outbuf == NULL) {
 			return PyErr_NoMemory();
 		}
+		Py_BEGIN_ALLOW_THREADS
 		buflen = strftime(outbuf, i, fmt, &buf);
+		Py_END_ALLOW_THREADS
 		if (buflen > 0 || i >= 256 * fmtlen) {
 			/* If the buffer is 256 times as long as the format,
 			   it's probably not failing for lack of room!