Research indicates that marriage equality legislation is associated with improved mental health outcomes for lesbian, gay, bisexual, transgender, and queer (LGBTQ) people. However, the public debate that often precedes such legislation may exacerbate psychological distress and minority stress. In 2017, the Australian Federal Government conducted a national survey to gauge support for marriage equality. The present study investigated the mental health of a sample of LGBTQ people during and after this survey period. A sample of 2,220 LGBTQ participants completed measures of psychological distress and minority stress during the survey period. Participants were invited for follow-up 1 week, 3 months, and 12 months after the postal survey results were announced. Data were analyzed using linear mixed models to evaluate change in psychological distress and minority stress across time points, and the influence of exposure to the marriage equality debate, sexual identity, and gender identity on psychological distress and minority stress. Reported symptoms of psychological distress and minority stress significantly decreased following the postal survey period. Greater exposure to the marriage equality campaign was associated with greater psychological distress and perceived stigma but not internalized stigma. Sexual and gender identity subgroups significantly differed on outcome variable means. This study documents the longitudinal effects on a minority group of a public vote and the enactment of legislation regarding their human rights. The results suggest the postal survey served as a significant stressor to Australia's LGBTQ community. Implications for policy and clinical practice are discussed. (PsycInfo Database Record (c) 2020 APA, all rights reserved).