This systematic review examines the effectiveness of occupation- and activity-based interventions on community-dwelling older adults’ performance of instrumental activities of daily living (IADLs). It was conducted as part of the American Occupational Therapy Association’s Evidence-Based Practice Project. Forty studies met the inclusion criteria and were critically appraised and synthesized. Within occupation-based and client-centered interventions, the evidence that multicomponent interventions improve and maintain IADL performance in community-dwelling older adults is strong. The results also indicate that client-centered, occupation-based interventions can be effective in improving and maintaining IADL performance. The evidence is moderate for functional task exercise programs and limited for simulated IADL interventions to improve IADL performance. In the area of performance skills, the evidence related to physical activity and cognitive skills training is mixed, and the evidence that vision rehabilitation interventions improve IADL performance in older adults with low vision is moderate. Implications for practice, education, and research are also discussed.