Context: The inclusion of interprofessional education opportunities in clinical placements for pre-registration learners has recently been proposed as a strategy to enhance graduates’ skills in collaborative practice. Objectives: A realist review was undertaken to ascertain the contexts, mechanisms and outcomes of formal interprofessional clinical workplace learning. Methods: Initial scoping was carried out, after which Ovid MEDLINE, CINAHL and EMBASE were searched from 2005 to April 2016 to identify formal interprofessional workplace educational interventions involving pre-registration learners. Papers reporting studies conducted in dedicated training wards were excluded, leaving a total of 30 papers to be included in the review. Results: Several educational formats that combined students from medicine, nursing, pharmacy and allied health professions were identified. These included: the use of engagement by student teams with a real patient through interview as the basis for discussion and reflection; the use of case studies through which student teams work to promote discussion; structured workshops; ward rounds, and shadowing. Meaningful interprofessional student discussion and reflection comprised the mechanism by which the outcome of learners acquiring knowledge of the roles of other professions and teamwork skills was achieved. The mechanism of dialogue during an interaction with a real patient allowed the patient to provide his or her perspective and contributed to an awareness of the patient's perspective in health care practice. Medication- or safety-focused interprofessional tasks contributed to improved safety awareness. In the absence of trained facilitators or in the context of negative role-modelling, programmes were less successful. Conclusions: In the design of workplace education initiatives, curriculum decisions should take into consideration the contexts of the initiatives and the mechanisms for achieving the education-related outcomes of interest.