Bi+ individuals face unique stressors such as anti-bisexual discrimination and internalized binegativity. Minority stress is associated with relationship dissatisfaction among sexual minority individuals, but this has rarely been studied among bi+ individuals, a population that experiences unique stressors related to relationships (e.g., assumptions of promiscuity and unfaithfulness). As such, the current study examined the associations between minority stressors and relationship satisfaction among bi+ individuals and potential differences in these experiences based on gender composition (same-gender, different-gender, at least one nonbinary individual) and partner sexual orientation (bi+, lesbian/gay, heterosexual). The sample included 358 bi+ adults in relationships who completed an online survey. Partial Pearson's correlations and one-way ANCOVAs were conducted, controlling for relationship length given its association with relationship satisfaction. Internalized and anticipated binegativity were negatively associated with relationship satisfaction, whereas outness was positively associated with relationship satisfaction. Anti-bisexual discrimination was not significantly associated with relationship satisfaction. Participants in relationships with bi+ partners reported lower anticipated binegativity than those in relationships with lesbian/gay or heterosexual partners and lower internalized binegativity than those with lesbian/gay partners. Those in relationships that included at least one nonbinary individual reported more anti-bisexual discrimination from heterosexual people than those in different-gender relationships. Internalized and anticipated binegativity may be risk factors for relationship dissatisfaction among bi+ individuals, whereas outness may promote satisfaction. Our findings establish a foundation for understanding risk and protective factors related to relationship dissatisfaction in this population.