Given the importance of their roles in society, the education of professionals is a central concern for providers and recipients of public services. In this article we consider the contribution of research on professional learning to current debate on the form and content of professional education. This mapping review asked, 'What does the research literature tell us about the characteristics of research into professional learning across professions?' We identified and synthesised primary research involving post-qualification professionals' professional learning. We searched seven databases using terms such as 'professional learning', 'professional development' and 'continuing education' from 2000 to date. We carefully screened articles against agreed criteria, extracted data and mapped the findings. After removing duplicates, 20,616 records remained. After full text screening, 356 articles were included: 266 from teaching (75%), 77 from healthcare (22%) and 13 from another profession or cross-professional (4%). Three included papers that spanned professions. Only 6% of articles studied the institution as the unit of analysis (rather than the individual). Around half of the included papers (49%) included an intervention. Most teaching interventions were proximal to the workplace whereas most healthcare/other studies were distal to the workplace, perhaps reflecting stage of development of the research field. Our study synthesised a heterogeneous literature to indicate the types or research that are needed to progress the debate. The clear differences in 'style' between professions suggested that collaboration could provide mutual benefit. Future research requires studies that report research in ways that lend themselves to evidence synthesis or replication.