Heterosexism is not only expressed through sexual prejudice as an external stressor, but also as an internalized rejection toward one’s own (and others’) sexually diverse identity. That is, lesbian women and gay men themselves internalize negative societal attitudes toward their sexual orientation and identity—a phenomenon called internalized homonegativity. A wealth of research shows that internalized homonegativity negatively affects the health and social adjustment of gay and lesbian people. However, the literature has documented this trend from an individual (over a dyadic) perspective, and largely among gay (over lesbian) samples. To address this oversight, we analyzed data from 210 gay and lesbian couples in Chile to examine both actor and partner effects of internalized homonegativity on their sexual satisfaction. Results from moderation analyses from an actor-partner interdependence model (APIM) approach show that partners’ internalized homonegativity negatively affects actor sexual satisfaction, a pattern significantly moderated by gender; that is, only observed among lesbian couples. Our results further demonstrated that these effects hold above and beyond the actor and partner effects of age and relationship satisfaction, as well as relationship length. These results are consistent with the broader literature, which discusses the specific features of internalized homonegativity in lesbian women, characterized—among other aspects—by restrictive social demands over their sexuality. Accordingly, our findings highlight the deleterious relational consequences of internalized homonegativity and offer a relevant empirical contribution to the understanding of specific minority stress dynamics among lesbian women.