Action learning sets (ALS) are used widely for organisational and workforce development, including in nursing (Anderson and Thorpe, 2004, Pounder, 2009 and Young et al., 2010). In the United Kingdom, a multi-faceted educational Pilot programme for new nurses and midwives was implemented to accelerate their clinical practice and leadership development (NHS Education Scotland, 2010). Action Learning Sets were provided for peer support and personal development. The Realistic Evaluation study reported in this paper explored issues of context, mechanism and outcome (Pawson and Tilley, 1997) influencing the action learning experiences of: programme participants (recently qualified nurses and midwives, from different practice settings); and programme supporters. A range of data were collected via: online questionnaires from 66 participants and 29 supporters; three focus groups, each comprising between eight and 10 programme participants; and one focus group with three action learning facilitators. The qualitative data pertaining to the ALS are presented in this paper. Thematic data analysis of context, mechanism and outcome configurations, generated five themes: creating and sustaining a collective learning environment; challenging constructively; collective support; the role of feedback; and effectiveness of ALS. Study outcomes suggest nursing and midwifery action learning should (a) be facilitated positively to improve participants' experience; (b) be renamed to avoid learning methodology confusion; and (c) be outcome focused to evidence impact on practice.