Learning in the teaching workplace is crucial for the development of all trainee teachers. Workplace learning is particularly important for trainee teachers in the lifelong learning sector (LLS) in the UK, the majority of whom are already working as teachers, tutors, trainers or lecturers while undertaking initial teacher education. However, literature indicates that LLS workplace conditions often inhibit teacher learning. This article reviews the research base on LLS trainees' workplace learning. Billett's (2008) concept of relational interdependence, between the affordances (activities and interactions) that workplaces offer for learning and the ways in which individuals perceive and engage with these, is used as a framework to synthesise research evidence. Support and experience of teaching were found to be crucial affordances for trainees' learning. The nature and availability of these affordances were shaped by workplace culture, organisational strategy, process and structures and the allocation and structuring of work. The ways in which trainees perceived and interacted with workplace affordances for learning were influenced by their prior experiences, confidence and self-esteem, career intentions, workplace position and status and orientation toward theoretical tools. The key properties of support and teaching experience and the workplace conditions needed to promote trainees' learning are proposed. These provide a starting point for employers, mentors, teacher educators, policy makers and trainees to improve workplace learning. The findings and proposals are also relevant to HE and school initial teacher education. Proposals are made for addressing the gaps in the scale and scope of research into LLS trainees' workplace learning.