Objectives: The authors investigated sexual orientation differences in risk for mental health morbidity, functional limitations/disability, and mental health services use among adults interviewed in the nationally representative 2013–2014 National Health Interview Survey. Method: Respondents were 68,816 adults (67,152 heterosexual and 1,664 lesbian, gay, and bisexual [LGB] individuals), age 18 and older. Fully structured interviews assessed sexual orientation identity, health status, and services use. Using sex-stratified analyses while adjusting for demographic confounding, the authors compared LGB and heterosexual individuals for evidence of mental health-related impairments and use of mental health services. Results: LGB adults, as compared to heterosexual adults, demonstrated higher prevalence of mental health morbidity and functional limitations. However, this varied by gender with LGB women evidencing elevated risk for both mental health and substance abuse (MHSA) and non-MHSA limitations. Among men, sexual orientation differences clustered among MHSA-related limitations. Overall, LGB adults were more likely than heterosexual adults to use services, with the source of functional limitations moderating these effects among men. Conclusion: MHSA-related morbidity is a significant concern among LGB individuals and is associated with higher levels of functional limitations/disability. The findings highlight that LGB persons use MHSA-related treatment at higher rates than heterosexuals do, and, among men, are more likely to do so absent MHSA or non-MHSA-related functional limitations. This presents a unique set of concerns within the integrated care setting, including the need to deliver culturally competent care sensitive to the context of probable sex differences among LGB individuals.