The Prophet Mohamed )Peace Be Upon Him( built the first mosque in Medina to define a worship place for Muslims. The Prophet, peace and blessings be upon him, began teaching people about their religion and life, enacting rulings, and building the Islamic state. As such, the Mosque, served as a court, community center, place for religious events and religious school. Today, mosques differ in their religious and societal role. Some of them are small mosques whose role is limited to holding prayers, some of them have a center for memorizing the Qur’an, others hold lessons, seminars, and seminars, and others are almost a university and an educational center in its own right. The main components of the mosque were: the praying area, the outside courtyard (Sahn), and an entrance covered by palm branches (arcade). Most of early Mosque design followed this general layout. Later, Mosque designs became more diverse and complex. Today, as Muslims adapted new ideologies, ceremonies, and techniques and blended them with vernacular Mosque designs, the design of Mosques are reimagined and are to complement to the urban fabric and the characteristics of the geographic surrounding. This study examines the evolution of mosques in Doha, the capital city of Qatar, Taking Al-Qubaiab Mosque, Education City Mosque as case studies. The main objectives of the study are: 1. Studying architectural styles of two different Mosques in different eras in Doha through analyzing architectural design and studying the plans, sections, and elevations so as to identify the spatial and functional relationships for the different parts of the Mosque and the principles that form it. 2. Identifying concepts, principles, and aesthetic values of the Mosque design & comparing Mosques with similar functions in various eras 3. Applying these concepts, principles, and aesthetic values in the contemporary Islamic architecture to ensure its continuity throughout the different eras