Objective: This study evaluated variation in substance use and mental health among graduate student subgroups. Participants: A sample of 2,683 master's and doctoral students completed an online survey in October 2017. Methods: Subgroup variation in behavioral health by demographic and program characteristics, particularly degree type and academic discipline, was explored. Results: Compared with academic doctoral students (ie, PhD students), professional doctoral students (ie, MD, JD, etc.) were significantly more likely to report high stress levels and moderate or severe anxiety symptoms. Master's students were more likely to report moderate or severe anxiety symptoms and use marijuana than academic doctoral students. Students in the behavioral and social sciences, social work, and arts and humanities disciplines were more likely to use substances and report mental health problems than engineering and business students. Conclusions: These findings highlight graduate student subgroups who might require closer attention with respect to access to behavioral health services.