Complex, systemic issues continue to challenge public services without respect for organisational and professional boundaries. In practice, collaborative working with others who have differing professional cultural norms and systems confront members with the need to learn about each other's values, priorities and practices. This paper explores the potential of action learning for the development of systemic leadership capabilities within public services. Starting from core principles it is argued that action learning be seen not simply as a small group process for problem-solving or individual development, but as a collective process for inquiring into and taking action on projects and practices within their complex, multi-agent contexts. (Contains 7 figures.)