In the essay, I want to disscuss Maritain's concept of freedom. If we want to understand some obscure thoughts about Maritain, we have to understand Thomas's thoughts. In the essay entitled ”The Conquest of Freedom.”, Maritain illustrates what freedom means. He indicates it is inseparable between the notions of personality and independent freedom .It is therefore necessary to study the Thomistic concepts of the will as nature (voluntas ut natura) and the will as reason (voluntas ut ratio). My purpose in this paper will be twofold: to consider first of all the differences which Maritain establishes between individuality and personality, and secondly, to understand what he says about freedom by placing it within the Thomistic context which is both philosophical and theological.