Voltaire, who takes place among philosophers of the age of enlightenment, is a philosopher who has stamped his age stamp with different views. His interesting side is not coming from his universality. He has become more prominent with his knowledge and creativity. Voltaire's idealism has found meaning in emotion rather than character. He is the one who has never lost the spirit of struggle throughout his life. In particular, he has resisted everything and everyone for the sake of prevailing of the fundamental such as reason, freedom, justice, and equality. With his thoughts, he fought against intolerance and the political influence of the church and his priests, and all irrational Christian dogmas. Today, his universal values are still being spoken for and contributed to the development of humanity. Voltaire lets Zadig, the hero of his work, go through a series of experiences. He makes him face all the challenges of life. Even if Zadig has difficulty from time to time in understanding what is happening, he comes back to life thanks to the new way out and has to believe that his destiny guides him in the progressive process. In this study, we will try to handle the concept of justice and happiness.