Objective To summarise research on the efficacy and safety of UK physician associates and anaesthetic associates in the context of an ongoing policy review. Design Rapid systematic review. Search strategy Keyword and author search of three databases; citation tracking; search of previous systematic reviews. Eligible studies Empirical research (any design) on physician associates/anaesthetic associates in UK healthcare published between 2015 and January 2025. Main outcomes Any measure of clinical efficacy or safety. Methods Eligible papers were grouped into categories and appraised using Critical Appraisal Skills Programme checklists. Two reviewers independently extracted data on study designs, samples, methods, and findings. Each paper was scored for trustworthiness, generalisability, and relevance; differences were resolved by discussion. Studies meeting a minimum inclusion standard were described and critiqued. Results Of approximately 5000 titles, 52 papers were eligible (48 on phys