Abstract
Agile software development addresses software process improvement within teams. Process improvement, although a central concept in agile development, is still hard to achieve. This paper argues for the use of diagnosis and action planning to improve teamwork in agile software development. Diagnosis and action planning is illustrated in a small and immature team and in a large and more mature team. The action planning focused on improving shared leadership, team orientation and learning. The improvement project provided most new insight for the mature team.