This study explored the intersection of masculinity and HIV care engagement among fishermen and other male fisherfolk on antiretroviral therapy (ART) in Wakiso District, Uganda. We conducted 30 in-depth interviews with men on ART recruited from HIV treatment sites and used a thematic analysis approach. Since HIV diagnosis and ART initiation, men had adopted masculine identities more conducive to HIV care engagement. The masculine roles of worker and provider, husband and sexual partner and the appearance of physical strength were compromised by HIV, but restored by ART's positive effects on health. Peers also emerged as facilitators to HIV care, with men supporting each other to seek testing and treatment. However, structural and occupational barriers to HIV care associated with the masculine role of worker remained a barrier to care engagement. Findings suggest that emphasising the benefits of ART in bolstering men's ability to fulfil the roles important to them may improve the effectiveness of HIV testing and treatment messaging for men. Differentiated care models that address structural-level barriers to care, and community-level gender-transformative programming to help fishermen engage in HIV care, may be beneficial.