Background There is a compelling rationale that effective communication between hospital allied health professionals and primary care practitioners could improve quality and continuity of patient care. It is not known which methods of communication are used, nor how effectively they facilitate the transition of care when a patient is discharged home from hospital. Our systematic review aims to investigate the methods and effectiveness of communication between hospital allied health professionals and primary care practitioners. Method Systematic review of quantitative and qualitative studies with narrative synthesis. Medline, CINAHL, EMBASE, PsycInfo and Proquest Nursing and Allied Health Sources were searched from January 2003 until January 2020 for studies that examined hospital allied health professionals communicating with primary care practitioners. Risk of bias in the different study designs were appraised using recognised tools and a content analysis conducted of the methodologies used. Results From the located 12,281 papers (duplicates removed), 24 studies met the inclusion criteria with hospital allied health professionals communicating in some form with primary care practitioners. There was, however, limited literature investigating the methods and/or the effectiveness of communication between hospital allied health professionals and primary care practitioners.Conclusion There is currently no 'gold standard' method or measure of communication between hospital allied health professionals and primary care practitioners. There is an urgent need to develop and evaluate multidisciplinary communication with enhanced health information technologies to improve collaboration across healthcare settings and facilitate continuity of integrated people-centred care.Registration: www.crd.york.uk PROSPERO CRD42019120410