Gay and bisexual men (GBM) are at risk of marginalization from outside and inside the gay community. Research consistently shows that biased societal attitudes and interactions with individuals outside the gay community (e.g., heterosexist discrimination) undermine well-being of GBM, but it has been unclear whether social interactions 'within' the gay community also affect well-being. It was recently recognized that some GBM perceive the gay community as stressful and that gay community members experience marginalization from other members (intragroup marginalization) based on personal attributes. However, not much is known about the lived and directly observed experience of intragroup marginalization from the perspective of GBM, nor have researchers outlined the breadth of reasons for intragroup marginalization. For the current qualitative study, which took place in 2021, 30 GBM (M-age = 31.07, SD = 9.04) residing in Australia participated in either an individual interview or a focus group discussion. The study utilized a descriptive qualitative approach to explore the experience of intragroup marginalization and to identify attributes that place GBM at risk of experiencing intragroup marginalization. Participants described their experiences and observations of intragroup marginalization in their social networks and indicated that marginalization from other GBM is common, harmful, and isolating, even more so than the impact of heterosexist discrimination. The results yielded a list of 19 personal attributes (i.e., physical, personal, behavioral, social, and sexual health) that can place GBM at risk of intragroup marginalization. Implications of findings are discussed to propose individual and community-based interventions and future research directions. Public Significance Statement<br /> This study reveals that gay and bisexual men (GBM) in Australia experience marginalization from other gay community members, based on their physical and personal qualities, behaviors, social connections, and sexual health. These experiences are described as harmful, isolating, and distressing. Recognizing these stressors for GBM could be important to improve well-being. Practitioners, policy makers, and LGBT+ support groups should consider these findings when developing inclusive interventions and support systems for this population.