Despite the long recognition in HRD theory that learning is socially and materially situated in activity and relations, HRD literature indicates a continuing strong emphasis on individualistic theories representing learning as knowledge acquisition or individual development. It is argued here that understandings of work learning within HRD theory can be fruitfully enriched by more fully incorporating practice-based perspectives. Three contemporary theories that analyse learning as a relation of individuals with/in activity have been selected for discussion here: the participational perspective of situated cognition, the notion of expansion from cultural-historical activity theory, and the constructs of translation and mobilization presented by actor-network theory. While these are not particularly new to HRD, the contribution of this discussion is to bring together these theories, along with published empirical workplace research based on them, to highlight selected dynamics that may be useful tools for HRD theory development. One element in particular is read across the three theories: the dialectic of 'flying' and 'grounding', or lines of discontinuity and continuity characterising work learning. The argument is theory-driven, drawing from HRD literature of work learning and practicebased theories of social activity and knowledge production.In the human resource development field, learning embedded in everyday work practice has been long recognized. Much HRD research has employed theories of informal and incidental learning, action learning, and conceptions of the 'learning organization' as a site of continuous collective knowledge-production. What these theories all have in common is emphasis on joint work activity as an important site for learning. This site exists alongside, but certainly not subordinate to, formal instruction such as training interventions. Practice-based theories also insist that learning cannot be considered solely an individual process. Learning is understood to emerge from relations and interactions of people with the social and material elements of particular contexts. Context is thus considered carefully in terms of its divisions of labour and power relations, environmental affordances, cultural disciplines, language, and so forth.These arguments have also occupied researchers in the broader social sciences, particularly in new sociology, feminist studies, cultural studies, critical management/organization