The purpose of this study was to examine the association between sexual identity-behavior concordance and discordance with meeting recommendations for 24-hour movement behaviors in adolescents. Participants were US adolescents who reported a history of sexual partners from the 2015-2019 National Youth Risk Behavior Survey (N = 19688; 49.3% female). A sexual identity-behavior variable indicated response agreement (concordance) and disagreement (discordance) between self-reported sexual identity and the sex of sexual partners. The 24-hour movement behaviors included meeting recommendations for physical activity, screen use, and school night sleep. Sex-specific and weighted multivariable logistic regression models were used to analyze associations between sexual identity-behavior concordance and discordance with meeting recommendations for 24-hour movement behaviors controlling for pertinent covariates. Discordant heterosexual males (OR = 0.47, p = 0.015), concordant gay males (OR = 0.31, p < 0.001), and bisexual males (OR = 0.39, p = 0.001) had lower odds of meeting physical activity recommendations compared to concordant heterosexual males. Bisexual males (OR = 0.44, p = 0.004) and bisexual females (OR = 0.73, p = 0.008) had lower odds of meeting screen use recommendations compared to concordant heterosexuals. Discordant heterosexual, concordant gay, and bisexual male adolescents were less likely to meet physical activity recommendations while there was a lower likelihood of meeting screen use recommendations in both male and female bisexual adolescents. Supplemental data for this article is available online at http://bibliotheek.ehb.be:2168/10.1080/19361653.2021.2010157