This systematic review presents research on the effectiveness of occupation- and activity-based interventions to improve everyday activities and areas of occupation and social participation for people with traumatic brain injury (TBI). Nineteen studies identified through a comprehensive database search were reviewed and synthesized into five themes: (1) multidisciplinary and interdisciplinary treatment approaches, (2) community-based rehabilitation programs, (3) treatment approaches using client-centered goals and relevant contexts, (4) social skills training and peer mentoring interventions, and (5) community mobility interventions. Evidence supports the use of multidisciplinary and interdisciplinary approaches across a variety of settings, with no single treatment approach or setting clearly superior to another. The specific contributions of occupational therapy practitioners and the nature of occupational therapy interventions have not been well studied, making it difficult to determine the extent to which occupation- and activity-based interventions provided by occupational therapy practitioners improve occupational performance and social participation after TBI.