Freedom of expression is one of the issues of concern to human societies in the contemporary world, because this issue is one of the most important basic rights of people in societies due to its special nature, and on the other hand, it is always in conflict with the authoritarian point of view. Islam accepts freedom of expression for everyone in the Islamic society, but it has specified limits and regulations for it. These restrictions and conditions, more than cumbersome and (...) intolerable regulations, are instructions for better use of freedom, which if not followed, not only the freedom of everyone in the society will not be realized, but also the category it will become anti-value and create cultural chaos. Imam Ali (peace be upon him), during his rule period, not only did not limit the freedom of expression, but also emphasized the expansion of this freedom. Based on Islam, since man is a free being, the privacy of his freedom must always be preserved; Therefore, freedom is the natural right of every human being and cannot be taken away from him. The practical life of Imam Ali (PBUH) and his advice to his agents in caring for freedom of expression in society and politics, bring its importance to the fore. Considering the importance of this issue, the purpose of this research is to study freedom of expression in Islamic teachings with emphasis on Nahj al-Balagha. Based on this, the related themes to freedom of expression have been extracted and explained from the point of view of Nahj al-Balagha, and conclusions have been presented in this regard. Contribution: This research showed that in the Islamic system, all citizens have the right to freedom of speech in ideological, political and social issues (according to the limits set by Islamic teachings and prevent the violation of Islamic values and other human values). These points are emphasized in Islamic teachings, especially in Nahj al-Balagha. (shrink)