Despite an increase in research examining sexual minority groups, there remains comparatively less targeted research with bisexual people, as they are often absorbed into lesbian and gay samples in research or disregarded entirely. Given the existing data suggesting that bisexual people have higher rates of mental health issues than lesbian women and gay men, it is critical that this group's mental health, and risk factors of mental ill-health, be explored independently. The current study aimed to investigate the risk factors of bisexual-identified individuals' mental health and suicidality using structural equation modeling (SEM). The study recruited bisexual people, with a final international sample of 817 participants aged between 16 and 58 years (M = 23.11, SD = 8.54). Results indicated high mental ill-health in this sample based on responses to mental health screening questionnaires, self-reported diagnoses, and reported engagement with mental health professionals. Participants also had a high degree of suicidality, with close to half reporting having made at least one suicide attempt and/or really wanting to die. Results of the SEM indicated that these poor mental health outcomes were associated with the unique experiences of prejudicial events (stigma, discrimination, interpersonal hostility), minority stress (internalized biphobia, lack of social support), and isolation from a welcoming community experienced by this population. We provide recommendations for clinical practice and educational programs in light of these findings.