Dialogue is one of the basic data of human existence where we find religious dialogue and civilizational dialogue, and there are educational dialogue, and cultural dialogue, and all of these types need interaction with the other that is intellectually, socially or religiously, and it is the only way through which contact is made between individuals, groups, peoples and states, and through it Human civilizations are advancing. And dialogue is extremely important in clarifying the true image that resides in the thought of the other side, especially that purposeful scientific dialogue, which deprives the interlocutors of fanaticism and extremism. Dialogue is also the first and essential step in building peace and consolidating peaceful coexistence in societies. Peace is defined as the absence of turmoil, violence, and wars, such as: terrorism, or religious, sectarian, or regional conflicts, for political, economic, or ethnic considerations. The definition of peace also comes in the sense of safety, stability and harmony; peaceful coexistence is defined as respect, acceptance and appreciation of cultural, religious and intellectual diversity between individuals. To achieve recognition of the right of others to enjoy their rights and freedoms. The aim of the research is to highlight the importance of religious dialogue in building peace and in establishing the principles of peaceful coexistence in multi-religious societies, especially our Iraqi society.