Masking can include suppressing or concealing certain behaviors to appear "non-autistic" and is one response to the excess social stressors of being a neurominority in a neurotypical-majority society. It is important to understand how persons who are multiply marginalized (e.g. an autistic person assigned female sex at birth who is bisexual), who experience multiple layers of excess social stressors, may face additional pressures to conceal their authentic selves. Autistic persons may be more likely than neurotypical persons to identify with a sexual minority orientation, such as asexual, bisexual, gay or pansexual. To advance our understanding of how marginalized identities may be associated with masking, we examined self-reported masking using the Camouflaging Autistic Traits Questionnaire in a sample of autistic adults (N = 462). After matching participants for assigned sex at birth and age, and after controlling for these effects in modeling, we found that sexual minority autistic adults reported significantly higher levels of masking relative to heterosexual autistic adults. We situate these findings within literatures on masking, minority stress, and stigma.