Bisexual individuals experience increased risk of mental health disorders compared to lesbian, gay, and heterosexual populations. This increased risk is theorized to arise from the stigmatization of bisexuality (i.e., anti-bisexual stigma). Research has linked anti-bisexual experiences with higher internalized binegativity (i.e., internalized anti-bisexual stigma), sexual identity uncertainty, and anxiety and depression. However, researchers have almost exclusively used cross-sectional designs, limiting our ability to draw conclusions about processes through which anti-bisexual stigma affects mental health. In the current study, we longitudinally examined a proposed bisexual-specific minority stress process in a sample of predominately White (92.2%), self-identified bisexual, cisgender women. Results provide support for the proposed process, indicating that experiencing more frequent anti-bisexual stigma predicted subsequent increases in internalized binegativity and sexual identity uncertainty. In turn, these increases in internalized binegativity were associated with concurrent decreases in strength of identification as bisexual, increases in strength of identification with monosexual identity labels (i.e., heterosexual, lesbian), and changes in visibility management strategies. These changes in identification were associated with concurrent increases in symptoms of anxiety and depression, and changes in visibility management were associated with increases in anxiety. Clinicians should consider this process when treating bisexual clients who present with psychological distress arising from anti-bisexual stigma.