Religion being raised  in the  international relations in recent decades. While religion has been known as an important issue  in  cultural diplomacy for decades, but it has engaged in new approaches recently. This article is aim  to evaluate the role of religion in the Saudi Arabia's cultural diplomacy. Moreover the study has focused on the efficiency of Muslim World League (MWL) in the context of Saudi Arabia's cultural diplomacy using Eytan Gilboa's models. Findings indicated that some reasons such as  locating the holy cities of Mecca and Medina in Saudi Arabia, historic conditions of  the country and also political competitions have led Saudi Arabia to focus on religion in its cultural diplomacy. In this regard MWL play an important role in  Saudi's cultural diplomacy success.