ABSTRACT: Importance:Recent evidence suggests that state policies affecting sexual minorities are associated with health disparities. Twelve states have laws permitting the denial of services to same-sex couples, and the US Supreme Court is considering whether states can prohibit the denial of services to same-sex couples. Objective:We investigated whether state laws permitting individuals to refuse services to sexual minorities were associated with changes in the proportion of sexual minority adults reporting mental distress. Design, Setting, and Participants:This difference-in-difference-in-differences linear regression analysis with state fixed effects used Behavioral Risk Factor Surveillance System (BRFSS) data from 2014 through 2016 from adults aged 18 to 64 years in 3 states that implemented laws permitting the denial of services to same-sex couples (Utah, Michigan, and North Carolina) and 6 nearby control states (Idaho and Nevada, Ohio and Indiana, and Virginia and Delaware, respectively). Sexual minority adults were defined as those who identified as gay, lesbian, bisexual, or not sure of their sexual orientation under a module on sexual orientation that BRFSS implemented in 2014 and each state could opt to include. Analysis controlled for year and individual-level sex, race, ethnicity, age group, educational attainment, income, employment, and marital status. A permutation test was conducted to precisely estimate statistical significance. Exposures:An interaction term indicating whether individuals identified as a sexual minority and lived in a state with a law permitting denial of services to same-sex couples in 2015. Main Outcomes and Measures:Mental distress, defined as poor mental health on 14 or more of the past 30 days. Results:Of 109 089 participants, 4656 (4.8%; all percentages incorporate survey weights) identified as sexual minorities, 86141 (72.1%) were non-Hispanic white, and ages were uniformly distributed between 18 and 64 years. In 2014, 2038 of 16637 heterosexual adults (12.6%) and 156 of 815 sexual minority adults (21.9%) in the 3 same-sex denial states reported mental distress. The proportion of sexual minority adults reporting mental distress increased by 10.1 percentage points (95% CI, 1.8 to 18.5 percentage points, permutation-adjusted P value = .046) between 2014 and 2016 in states that passed laws permitting denial of services to same-sex couples compared with control states, a 46% relative increase in sexual minority adults experiencing mental distress. Laws permitting denial of services to same-sex couples were not associated with significant changes in heterosexual adults experiencing mental distress (-0.36 percentage points, 95% CI, -1.73 to 1.01 percentage points). Conclusions and Relevance:Laws permitting denial of services to same-sex couples, which exist in 12 states and are under consideration by the US Supreme Court, are associated with a 46% increase in sexual minority adults experiencing mental distress.