BACKGROUND: It is recommended that allied health professionals (AHPs) participate in regular clinical supervision (CS). However, AHP understanding of CS processes and outcomes is unclear. This systematic review reports the evidence for CS for AHPs and other health professionals. METHODS: Five databases and reference lists of included articles were searched. Papers included described CS definitions, processes and outcomes of CS. Due to the paucity of CS research for AHPs, nursing and medical disciplines were included. Two reviewers critically appraised the 33 included papers. RESULTS: The majority of papers were exploratory. Definitions and processes for CS were not clearly identified. Outcomes of CS included the relationships between CS and job satisfaction and workplace stress. Proctor's model and the Manchester Clinical Supervision Scale were the most common framework and evaluation approach. Contradictory positions of which components of Proctor's model should be included in CS were reported. Methodological flaws and a lack of comparative studies were common. DISCUSSION: Although not extensively supported by evidence, CS was generally held to be a positive experience and tends to be provided without a clear definition or model, using new or untested tools. Further research to evaluate CS for AHPs, is needed.