The experience of serious mental illness (SMI) is unique for transition-age youth (16-29 years old), as this marks a critical life stage characterized by contemporaneous transitions in one’s psychosocial, physical, and occupational development. New research agendas centred on youth resilience (e.g., processes of positive adaptation in response to adversity) have emerged to manage SMI, yet not systematically synthesized. The present scoping review aimed to map how resilience has been conceptualized among transition-age youth diagnosed with SMI, explore resilience factors and outcomes, and identify current knowledge gaps. Consultations were conducted during the review process to incorporate feedback from transition-age youth with SMI, mental health clinicians, and researchers (N = 20). Data were analyzed using meta-narrative review and content analyses. Twenty-four eligible articles were organized into four research traditions: Stress Adaptation, Person-Environment Interactions, Recovery-Focused, and Critical & Cultural Perspectives. A wide range of resilience factors and outcomes were synthesized into a Process Model of Resilience, extending prior frameworks by adding health service-related factors as a central component unique to this population. Specific self-regulatory strategies have been under-researched (e.g., strategies / mechanisms through which young people self-manage their mood, thoughts, behaviours), with no studies examining the role of physical activity engagement. Community advisors further emphasized a need for patient-oriented research that recognizes the connection between youth’s physical and mental health. Results highlight an opportunity within exercise psychology research to advance understandings of how lifestyle psychiatry, physical activity, and mind-body practices can positively contribute to processes of resilience among young people living with SMI.