This paper provides a comparative analysis of green building strategies in circular cities from an architectural perspective. It focuses on Belgrade, Serbia, which has a temperate continental climate, and Podgorica, Montenegro, with a mild subtropical climate. The data were gathered through an online questionnaire disseminated among 140 architects in both cities. A five-point Likert scale was applied, and the data were analyzed using the Statistical Package for the Social Sciences (SPSS, version 23). Descriptive statistics, factor analysis, reliability testing, and group comparison methods were employed to ensure a valid, reliable, and transparent framework for processing and interpreting the research of data. By analyzing locally available materials, technologies, and climate factors, the research found that the adoption of circular economy principles does not significantly differ between the cities. This suggests that economic and policy-related factors may have a greater influence than initially expected. Additionally, there was no significant difference in the integration of greening strategies integration (p = 0.08), challenging the assumption that climate-responsive design would lead to distinct variations in urban form. However, locally available materials and technologies had a stronger impact on green building practices in Serbia (p = 0.01). The study highlights that sustainable architecture is shaped by a combination of local resources, regulatory frameworks, and socio-economic conditions rather than climate factors alone. These insights contribute to the theoretical advancement of climate-smart green building strategies in circular cities. They provide valuable guidance for practitioners and policymakers. Future research should further explore the interplay of socio-economic and regulatory influences to refine strategies for climate-responsive and circular architecture.