This article investigates the effects of different facets of school leadership (transformational, instructional and collaborative leadership) on the improvement of teaching following an inspection with respect to the innovation capacity of teachers, the quality of within school collaboration and use of feedback from school inspection. Analyses are based on data from n=933 teachers within 83 Lower-Saxony schools by applying a structural equation which has previously been designed and employed by Leithwood et al. (2006; 2002; 2008). The empirical model fits very well. The results show that transformational leadership has the biggest total effect on the improvement of teaching following an inspection, although no direct effects on the dependent variable are detectable. The effects of instructional leadership are somewhat smaller, but direct effects are statistically significant. Furthermore, the extent in which data from an inspection is used by teachers predicts the improvement of teaching after an inspection. The negative effect of teacher collaboration on the improvement of teaching is unexpected.