Bisexual and other non-monosexual (bi+) people are at increased risk for depression and anxiety compared to both heterosexual and gay/lesbian people. Bi + people are also more likely to conceal their sexual orientation than gay/lesbian people are, and concealment is generally associated with negative mental health outcomes. Despite evidence that concealment is a particularly salient stressor for bi+ people, there has been a lack of attention to their motivations for concealment. As such, the goal of the current study was to examine the associations among concealment, motivations for concealment, and depression and generalized anxiety symptoms in a sample of 715 bi+ people who completed an online survey. Nearly half of participants endorsed purposely trying to conceal their bi+ identity in their day-to-day life, and concealment was significantly associated with higher levels of depression and generalized anxiety. Using exploratory factor analysis, we identified two motivations for concealment: intrapersonal motivations (e.g., one's bi+ identity not being a central part of one's overall identity, not being comfortable with being bi+) and interpersonal motivations (e.g., concern about being judged or treated negatively, concern about putting oneself at risk of physical harm). Interpersonal motivations were significantly associated with higher levels of depression and generalized anxiety, whereas intrapersonal motivations were not. In sum, while concealment may generally be associated with negative mental health outcomes, this may only be the case for those who conceal out of concern for discrimination and victimization. These findings highlight the importance of examining bi+ people's motivations for concealing their sexual orientation in order to understand the extent to which they experience negative mental health outcomes.