Objective: The current study examined constructs that may buffer effects of minority stress on substance use and mental health in LGBTQ+ (lesbian, gay, bisexual, transgender, queer+) postsecondary students. Participants: Online survey data from 435 LGBTQ+ college students throughout Oregon were used. Methods: Structural equation models examining distal minority stress, belonging/support, and their interaction as predictors of substance use (alcohol, cannabis, cigarette, and e-cigarette use) and past 30-day psychological distress in separate models. Results: The only identified significant interaction was between institutional belonging and distal minority stress for the distress outcome, suggesting higher levels of institutional belonging buffered the associations between distal minority stress and distress. Distal minority stress was associated with higher distress scores, and family support and friend support were associated with lower distress scores. Conclusions: Findings highlight how interventions or policies to improve campus climate and social support for LGBTQ+ students could confer benefits to LGBTQ+ students' wellbeing.