This study examines the physical features of traditional mosques in the Quzzat (Bardrani) quarter of Herat Old City, Afghanistan. Traditional mosques are constructed with locally available materials and are planned based on cultural and climatic conditions. Mosques are categorised as modern or traditional. Traditional mosques are divided into three subcategories: preserved, damaged (defaced), and transformed. Transformed mosques are formerly traditional mosques reconstructed with modern or industrial materials (concrete and reinforcement). This study explores the distribution of mosques and analyses their plan typology. Mosques are categorised into five plan types, and three relative case studies are described in detail to provide a better understanding and an in-depth analysis of mosque typology.