Although gender mainstreaming in science, engineering, and technology education has continued to receive research attention, not much has been done in architecture. This study investigated the interaction patterns in architectural design studios and classrooms in the Nigerian university context to suggest how gender mainstreaming can be achieved in architecture education. Twelve Architecture Lecturers and 837 students drawn from three universities in Southern Nigeria were involved in this research. The data were collected via studio and classroom observations using a modified Flanders Interaction Analysis Categories and questionnaire and analysed using descriptive statistics, analysis of variance, and Scheffe’s pairwise comparison. The results revealed that the competitive pre-dominated the cooperative interaction pattern but the female group was better in the cooperative pattern than the male group who did better with the competitive pattern. Gender was identified as the main factor influencing the predominant interaction pattern in architectural design studios and lecture rooms investigated. The study implies that for a successful gender mainstreaming in architectural education, effective integration of both the cooperative and competitive interaction patterns with the former dominating over the latter is required in architecture studios and lecture rooms in Nigeria and other countries with similar experiences.