Objectives. Only a few studies have explored the association between social support and resilience, coping style, and posttraumatic growth (PTG) in breast cancer. The current research aimed to identify the latent subtypes of social support in patients with breast cancer (BC) who underwent surgery. Moreover, the mediating role of resilience and the moderating role of coping style were investigated. Methods. This cross-sectional study enrolled 115 patients from Be Resilient to Breast Cancer between September 2021 and April 2022 using the convenience sampling method. Then, the Perceived Social Support Scale, Connor-Davidson Resilience Scale, Medical Coping Modes Questionnaire, and Posttraumatic Growth Inventory were utilized. A latent profile analysis and a moderated mediation analysis were performed. Results. Three subtypes of social support were identified as low (16.5%), middle (53.0%), and high (30.4%). Social support, resilience, and coping style were found to be positively associated with PTG (r = 0.373, P < 0.01; r = 0.427, P < 0.01; r = 0.218, P < 0.05). Resilience played a significant role in mediating the association between social support and PTG (P < 0.05). However, coping style did not significantly moderate the association between resilience and PTG (P > 0.05). Conclusions. Heterogeneous subgroups of social support have been identified in patients with BC. Resilience significantly mediates the association between social support and PTG. Meanwhile, coping style does not significantly moderate the association between resilience and PTG.