Purpose: School improvement and effectiveness depend substantially on teachers developing their professional competencies on an ongoing basis. Germany's new approach to school governance combines instruments borrowed from different theoretical concepts: teacher collaboration (in a sense of professional self-regulation with high autonomy) and individualized staff development by principals (in a sense of managerial self-regulation with high within-school accountability). The purpose of the study is to examine whether these instruments are applied at schools in Germany, what factors predict the extent of use, and if the use is associated with the improvement of teachers' instructional competencies. Design/methodology/approach: In order to answer our research questions, we conducted a standardized teacher and principal survey at primary and secondary schools in Germany (658 teachers from 51 schools). Findings: The analyses indicate that the instruments are not being carried out across the board. The results of a multilevel path analysis furthermore show that teacher self-efficacy, principals' leadership behavior, school size and students' SES are important preconditions for the use of the two instruments. However, the instruments have an impact on the improvement of teachers' instructional competencies but through different pathways. Research limitations/implications: Limitations concern the cross-sectional design of the study and the focus on measures based on retrospective self-reported data. Originality/value: This study is the first that examines the implementation and impact of two instruments with differing governance theoretical background in German schools.