OBJECTIVES: We investigated how internalized homonegativity and dyadic stress predicted relationship satisfaction in same-sex romantic relationships and explored the moderating roles of dyadic coping and relationship duration in the aforementioned associations. METHODS: The actor-partner interdependence moderation model (APIMoM) was introduced to deal with mutual influences between both partners in 241 same-sex romantic relationships. RESULTS: (1) individual internalized homonegativity, dyadic stress, and dyadic coping predict their own relationship satisfaction (i.e., actor effect); (2) individual dyadic stress predicts their partner's relationship satisfaction (i.e., partner effect), but only for those with a shorter relationship duration (i.e., ≤ 36 months); and (3) dyadic coping buffers the effect of individual dyadic stress on their own relationship satisfaction, but only for those in the group with a longer relationship durations (i.e., > 36 months). CONCLUSIONS: These findings highlight the importance of a dyadic approach to further understand the impact of stress on relationship satisfaction. We reflect that interventions on couple-oriented coping could improve relationship well-being and sexual health among same-sex couples.