As a result of reforms in the governance of schools, the role of principals in Germany has changed from a teacher with additional administrative tasks to a leader of school improvement. However, many principals in Germany did not receive any substantial formal training for management and leadership tasks. Using the results of a survey of 1240 principals in nine German states, we investigated in which areas of school improvement German principals had professional development needs and how their needs were related to individual and school-related factors. Despite a lack of training and in contrast to studies from other countries, principals reported only moderate professional development needs, and these were influenced, only to a limited extent, by their training and experience and, to a greater extent, by the individual self-efficacy and the perception of teachers in schools. The results might indicate that the normatively postulated change of the principal's role has not yet permeated their practice.