Dartmouth’s NIDA-funded T32 Science of Co-occurring Disorders training program offers a unique experience in transdisciplinary research related to substance use, addiction, and commonly co-occurring mental, behavioral or medical disorders. Multiple interconnected research groups provide training and research opportunities in social, behavioral, and neurobiological mechanisms, treatment development (psychosocial and pharmacological), digital approaches to assessment, therapeutics, and dissemination, and health services practices and implementation. This dynamic, mentor-oriented training program accommodates 4 NIDA-funded postdoctoral and 3 predoctoral positions and additional trainees funded by alternative sources of support.