The present study aims to explore the perceived factors affecting student-teachers' (STs) learning about social urban sustainability. Participants were 63 STs enrolled in a Department of Primary Education located in Northern Greece. Although the participants were aware of the principles of sustainability and education for sustainability, none of them had familiarity with social or urban sustainability. Reflective group discussions, in the form of semi-structured interviews, at the end of the course, each one lasting about 30 min, served as the data source. Data were subjected to qualitative analysis employing bottom-up development of categories. The results indicate that teaching methods associated factors, like the practical nature of the course and classroom discussions, along with the use of proper teaching tools and activities, including site visits, and concept maps, were the main factors affecting STs' learning, suggesting a strong and constructive combination between theory and praxis for the advancement of STs' learning. Moreover, the provision of multiple learning environments to learners was also a prerequisite for effective learning.