Religion is regarded as a decree from God and is an important institutional structure that complements the social system. Islam arrived in Indonesia in the 13th and 16th centuries AD, and is now the second largest religion in the world after Christianity. Culture also plays a significant role in shaping religious identity. Religion and culture are two distinct yet important and sensitive entities in the social environment. Both are primordial aspects inherent to communities and individuals and influence each other. Culture can influence religious views, and vice versa, religion can influence culture. In this article, the author uses a qualitative literature study method to provide a deeper understanding of the relationship between religion and culture in Islam as well as how culture affects the formation of religious identity. The purpose of this article is also to explain how the concept of social justice in Islam can bring harmony between different cultures.