Introduction: The Cognitive Orientation to daily Occupational Performance (CO-OP) approach is a client-centered, performance-based intervention widely applied in occupational therapy. While its effectiveness for occupational performance is established its impact on executive functions (EFs) across diverse populations remains less clear. Aim: To examine the evidence regarding the effectiveness of the CO-OP approach on EFs among diverse populations. Method: A systematic search of PubMed, CINAHL, AMED, MEDLINE, PsycINFO, Scopus and Proquest was conducted following the Cochrane Handbook. Nine studies met the inclusion criteria, including randomized controlled trials and case-control designs. Results: Across 141 participants, improvements were found based on EF assessment tools, in planning, problem-solving, attention, cognitive flexibility, and self-regulation, though results varied between populations. Studies involving children reported notable gains in problem-solving and planning, while research with adults with TBI, ABI, or post-stroke conditions indicated more variable results. Almost all studies reported significant improvements in occupational performance. Conclusions: Findings suggest that the CO-OP approach can effectively enhance key components of EFs across a range of populations Significance: This review expands existing knowledge by integrating findings across populations, strengthening the link between executive functioning and occupational performance, and supporting CO-OP’s adaptability in occupational therapy practice.