This study adopts an urban form typology approach to better understand the energy performance of apartment complexes in Seoul. Apartment complex typologies were identified using the Gaussian mixture model (GMM), an unsupervised learning method, and annual, summer, and winter building electricity uses were compared with the Analysis of Variance (ANOVA) and Games‒Howell post hoc test. Monthly electricity use patterns were then identified with k-shape clustering for different apartment complexes, and their correspondences with apartment typologies were analyzed. The results show that Seoul has three apartment typologies (flat-type low-density typology, flat-bent-type mid-density typology, tower-mixed-type high-density typology) and three electricity use patterns (summer-peak-month dominant pattern, summer-dominant pattern, winter-dominant pattern). Among apartment typologies, the tower-mixed-type high-density typology has the highest electricity consumption and the highest ratio of the summer-peak-month dominant pattern compared to other typologies. Flat-bent-type mid-density typology has the lowest electricity consumption and the lowest ratio of summer-peak-month dominant pattern compared to other typologies. The findings from this research could help urban planners and designers better understand the relationship between apartment form types and building energy use patterns to develop energy-efficient urban forms.