A constant yet complex question in the history of political thought is that of justice, which has been discussed by all political thinkers. Yet, different answers have always been provided to the question what justice or a just act is or what decision can be considered to be a just one. Nevertheless, as a concept throughout history, justice is also a topic constantly dealt with in divine religions, especially in Islamic thought. In Islamic thought, justice is by itself of such significance that it has been frequently discussed in the Holy Quran as well as in the tradition and, subsequently, has been one of the most controversial religious concepts analyzed by Islamic thinkers including philosophers, theologians and Islamic jurisprudents. The present article studies the concept of justice according to Imam Ali, especially because he is the only Infallible Imam throughout the history of Islam who functioned as the head of the political power and led the Islamic society through complex political events and with wide gaps.