This review uses research literature to outline the characteristics, benefits and disadvantages of formal, non-formal, and informal learning. There appears to be a consensus around the meanings of formal and informal learning. Formal learning broadly aligns with organised, institutionalised learning models (such as learning seen in schools), whilst informal learning describes the everyday learning that people experience throughout their lives, and which can go easily unrecognised. Non-formal learning is less clearly understood. Despite its specific use in various cross-national policy contexts (e.g., Council of Europe, 2022; OECD, n.d.), it is most easily understood in its negative sense, i.e., as being 'not formal', so it is pertinent to explore its meaning. We use this review specifically to build a better understanding of non-formal learning and to consider the methodological implications for researching this type of learning. This literature review process had three steps: literature source identification, search criteria definition, and document coding.