Informed by structural stigma theory, this article presents the results of two studies that explored mental health experiences of transgender, nonbinary, and gender-diverse (TNG) individuals and cisgender lesbian, gay, bisexual, and queer (LGBQ) individuals (N = 523) prior to and following a state referendum to remove gender-based protections. In the Preelection Study, a path model explored relationships among individual factors (i.e., TNG identity, history of gender-based victimization), interpersonal variables (i.e., Referendum familiarity, exposure to Referendum-related messages, sexual orientation, and gender identity-specific social support), and mental health factors (i.e., Referendum-related anxiety and depressive symptomatology). Referendum-related anxiety mediated the relationships between TNG identity, gender-based victimization, sexual orientation and gender identity social support, and depressive symptomatology, explaining 40% of the variance in depressive symptomatology. Postelection, a subsample of participants (N = 117) was used to test a model of differences from pre- to postelection. Neither TNG identity nor victimization predicted Postelection mental health, however, Referendum-related anxiety and depressive symptomatology were significantly lower following the ballot vote that retained gender-based rights. Clinical implications suggest sexual and gender minorities may report increased anxiety in the face of anti-lesbian, gay, bisexual, transgender, and queer (LGBTQ) legislation, which may be associated with heightened symptoms of depression. TNG people and LGBTQ people with histories of gender-based victimization may be more at risk for mental health concerns related to anti-TNG legislation. (PsycInfo Database Record (c) 2022 APA, all rights reserved)