Transgender and gender diverse (TGD) students often face discrimination, harassment, and inadequate support in educational settings, leading to increased stress and negative health outcomes. This study investigated differences in perceived social support from various sources and types between TGD students and their cisgender peers, and how this support is associated with school belonging. A total of 744 middle school students from a Midwestern US school participated in the survey, including 60 students who identified as TGD. Compared to cisgender students, TGD students reported lower levels of social support from all sources (teachers, peers, and parents) and types (emotional, appraisal, instrumental, and informational). Teacher support was positively associated with school belonging for TGD students, while parent support was negatively associated. Among TGD students, appraisal and informational support were positively associated with school belonging, while emotional and instrumental support showed no significant associations. For cisgender students, all types of social support were positively associated with school belonging. These findings highlight the unique challenges faced by TGD students in terms of social support and school belonging, and implications are discussed.