ImportanceSexual and gender minority (SGM) adults in the US are more likely than their non-SGM counterparts to provide informal care to their family members and/or friends. Caregiving can impose substantial physical, mental, and social connection issues on caregivers.ObjectiveTo examine the associations among loneliness, lack of social and emotional support, sexual orientation, gender identity, and informal caregiving status.Design, Setting, and ParticipantsThis population-based, cross-sectional study used data from the 2022 Behavioral Risk Factor Surveillance System collected from noninstitutionalized US civilian residents aged 18 years or older. Data analysis was conducted from June to July 2024.Main Outcomes and MeasuresThe primary dependent variables included self-reported dichotomized (yes vs no) loneliness and lack of social and emotional support. The primary independent variables were sexual orientation (straight, gay or lesbian, bisexual, or something else), gender identity (cisgender and transgender), and informal caregiving status (yes vs no). A binomial distribution and log link function were used to derive adjusted prevalence ratios (APRs) and their respective 95% CIs for each outcome measure.ResultsThe analytic sample included 43 693 US adults (23 223 [51.6%] female at birth). In multivariable regression analyses adjusting for sociodemographic and health factors, among caregivers only, and compared with straight individuals, loneliness was significantly more likely among lesbian or gay individuals (APR, 1.30; 95% CI, 1.11-1.51), bisexual individuals (APR, 1.26; 95% CI, 1.12-1.43), and those who identify as something else (APR, 1.26; 95% CI, 1.09-1.46). Similarly, for noncaregivers, lesbian or gay individuals (APR, 1.34; 95% CI, 1.15-1.57), bisexual individuals (APR, 1.47; 95% CI, 1.34-1.61), and individuals identifying as something else (APR, 1.41; 95% CI, 1.25-1.58) experienced significantly higher risk of loneliness than straight noncaregivers. Transgender caregivers were more likely than cisgender caregivers to report loneliness (APR, 1.34; 95% CI, 1.24-1.46). In terms of lack of social and emotional support, bisexual caregivers (APR, 1.21; 95% CI, 1.00-1.48) and caregivers identifying as something else (APR, 1.34; 95% CI, 1.09-1.66) were significantly more likely than straight caregivers to report a lack of social and emotional support. Similarly, both bisexual noncaregivers (APR, 1.44; 95% CI, 1.28-1.63) and noncaregivers identifying as something else (APR, 1.38; 95% CI, 1.18-1.61) experienced a significantly higher risk of lacking support compared with straight noncaregivers.Conclusions and RelevanceIn this cross-sectional study of social connections, SGM adults experienced significantly higher levels of loneliness compared with straight adults, irrespective of caregiving status. Furthermore, caregiving exacerbated these disparities across SGM subgroups. Patterns of lack of social and emotional support mirrored those of loneliness across different SGM and caregiving subpopulations, with nuances emerging upon adjustment for individual characteristics.