The interest in research focusing on learning taking place at work, through work and for work has considerably increased over the past two decades. The purpose of the paper is to review and structure this wide and diverse research field. A tentative holistic model--the 3-P model of workplace learning--is presented, in relation to which the following six lines of research are identified: (1) studies describing the nature of workplace learning, (2) research on work identities and agency in workplace learning, (3) studies on the development of professional expertise, (4) analyses of competence development in education-work contexts in vocational education and training as well as in higher education, (5) research on communities of practice, and (6) research on organisational learning. The research lines and the holistic 3-P model should be seen as analytic tools for understanding the diversity in workplace learning research. They may also serve as a kind of map for individual researchers, helping them to locate their main areas of interest in this broad field of research and to outline research designs for future studies.