This study explored the influence family relationships have on HIV-related factors among Hispanic or Latino/a/x Mexican sexual minority cisgender males in San Antonio, TX, US. A total of 15 young adults (7 people living with HIV; PLWH) ages 21-30 completed a semi-structured interview. Data were transcribed verbatim and analyzed using thematic analysis. The following themes emerged: (1) family support; (2) mother-son relationships; (3) father-son relationships; (4) sibling support; (5) family marginalization of sexual minorities; and (6) internalized homophobia. People who reported being HIV negative were more likely to have a prominent mother-son relationship, strong sense of family, supportive siblings, and family acceptance as a sexual minority. PLWH were more likely to report a weak sense of family, being raised in a maternal-led household, and less likely to have a relationship with their father and siblings. Marginalization among participants regardless of HIV status included exposure to religious rhetoric stigmatizing sexual minorities and fathers' reinforcing Mexican traditional gender norms. In addition to encountering homophobia, PLWH were further marginalized by family members due to their HIV status. The findings suggest a need for greater attention to examining the impact of familial support of Hispanic or Latino/a/x Mexican sexual minority cisgender males as young adults with or at risk of HIV.