Purpose: Multi-level hostility toward sexual minority (SM; includes, but is not limited to those identifying as gay, lesbian, bisexual, queer, or same-gender loving) and other minority populations (e.g., racial/ethnic) increased after the 2016 U.S. presidential election. This may generate stress and mental health problems among those groups, and particularly among SM people of color. This study assessed whether the mental health of Black and Latinx SM adults declined after the 2016 U.S. presidential election. Methods: Data were from a daily national probability survey (thus, mean changes in mental health outcomes over time may reflect population shifts in mental health) of Black and Latinx SM adults (N = 537), recruited 7 months before and 17 months after the November 8, 2016 election. Using a between-subjects design, spline-based regressions (spline set at election date), adjusted for sociodemographic characteristics, estimated four mental health outcomes (past-month number of "poor mental health" days and psychological distress, past-year suicidal ideation, and social wellbeing) as a function of survey completion date. Results: There was marked worsening in each of the mental health outcomes over the postelection period (past-month poor mental health days, B = 0.05, standard error [SE] = 0.02, p < 0.05; psychological distress, B = 0.28, SE = 0.14, p < 0.05; suicidal ideation, odds ratio = 1.13, 95% confidence interval >1.00-1.26, p < 0.05; and social wellbeing, B = -0.05, SE = 0.02, p < 0.05). None of the outcomes varied over the pre-election period. Conclusions: This study provides evidence of worsening mental health among Black and Latinx SM adults in the United States during the 1.5 years after the 2016 U.S. presidential election.