ABSTRACT: BACKGROUND:In 2012, the U.S. Food and Drug Administration proposed nine graphic health warnings (GHWs) on cigarette packaging that were rated equally effective across racial/ethnic, education, or income groups of adult smokers. However, data on GHW effectiveness among sexual and gender minority (SGM) adults, who have higher smoking prevalence, are currently lacking. This study analyzed whether perceived effectiveness of GHWs differed by gender and sexual orientation. METHODS:Data came from a randomized experiment among 1,200 adults with an oversample from low socioeconomic status groups, conducted between 2013 and 2014 in three Massachusetts communities. Participants viewed and rated the effectiveness of nine GHWs. Mixed effects regression models predicted perceived effectiveness with gender and sexual orientation, adjusting for repeated measurements, GHWs viewed, age, race, ethnicity, smoking status, and health status. RESULTS:Female heterosexuals rated GHWs as more effective than male heterosexual, lesbian, and transgender and other gender respondents. There was no significant difference between female and male heterosexuals versus gay, male bisexual, or female bisexual respondents. Differences by gender and sexual orientation were consistent across all nine GHWs. Significant correlates of higher perceived effectiveness included certain GHWs, older age, being African-American (vs white), being Hispanic (vs non-Hispanic), having less than high school education (vs associate degree or higher), and being current smokers (vs non-smokers). CONCLUSIONS:Perceived effectiveness of GHWs was lower in certain SGM groups. We recommend further studies to understand the underlying mechanisms for these findings and investments in research and policy to communicate anti-smoking messages more effectively to SGM populations.