For the past 50 years, organizations and individuals around the world have reported success in their use of action learning programs to solve problems, develop leaders, build teams and transform their corporate cultures. However, very little rigorous research has been conducted to determine the effectiveness of action learning. The authors reviewed 21 refereed articles, theses and dissertations that quantitatively and/or qualitatively measured the impact of action learning and to determine the success factors in action learning programs. The evidence elicited from these studies support the following: (1) action learning develops broad executive and managerial leadership skills, particularly collaborative leadership and coaching skills; (2) action learning improves the ability of managers to develop integrative, win/win solutions to conflict situations; (3) governing variables that were consistently identified as critical to the success of action learning include questioning, taking action, learning from group members, listening, group diversity, feelings of confidence and well-being, safe environment, and the presence of a coach; and (4) significant factors for conducting successful action learning programs involved: (1) "team-level processes" of skilled coaching, diversity, self-directed team processes, effective team presentations and review of team processes; as well as (2) "organization-level" processes of ensuring implementation of solutions, alignment and importance of the problem, support of top decision makers and the leveraging of organizational resources. (Contains 2 tables and 2 notes.)