Sexual minorities are known to experience wide-ranging mental health disparities; however, little work has experimentally examined risk-factors explaining these disparities. Minority stress experiences, such as discrimination based on sexual orientation, are among the leading drivers of adverse mental health outcomes among this population, but other risk factors may also contribute. Peer influence is a common risk factor for externalizing disorders such as substance abuse among the general population, although peer influences on risk behavior among sexual minorities are understudied. A growing body of literature has elucidated potential mechanisms of disorder development and maintenance, particularly minority stress, although claims of causality are limited due to the lack of experimental evidence. Therefore, the present study sought to examine both minority stress and peer influence as potential causes of risk behavior. Adults (n = 504; n = 247 sexual minority) completed an online task in which they made choices between risky and safe bets both in the presence and absence of others’ choices (peer influence). Participants were randomized to either a minority stress or neutral control condition before completing the task. Results indicate that sexual minorities and heterosexuals did not differ on risky decision-making in the absence of others’ choices, even after minority stress induction. However, on trials in which participants could see the other players’ choices, sexual minorities made significantly more risky choices after being exposed to minority stress on certain trail types. Further, results from computational modeling of choice behavior showed Group (sexual minority or heterosexual) X Condition (minority stress or neutral) interaction such that sexual minorities in the neutral condition relied more on other’s choices to make their own, while sexual minorities in the minority stress condition showed a reduction in peer influence on their own choices. These results indicate that minority stress exposure modulates peer influence’s effect on decision-making, potentially serving as a risk factor for adverse outcomes.