In Nordic countries, as well as in the Netherlands, schools have high school autonomy (OECD, 2016 [Netherlands 2016 Foundations for the Future. https://www.oecd.org/netherlands/netherlands-2016-9789264257658-en.htm]; Tolo et al., 2020 [Intelligent accountability in schools: A study of how school leaders work with the implementation of assessment for learning. "Journal of Educational Change," 21(1), 59-82]). In schools there are both horizontal and vertical working relations and all teachers and school principals within a school are expected to take responsibility for collaborative-innovation practices (CIP). In this paper, we describe a study investigating how both horizontal and vertical working relations relate to CIP. We used longitudinal questionnaire (2036 teachers, 157 schools) and interview data (53 teachers, 20 schools). These data were gathered in Dutch schools participating in the large-scale 'LeerKRACHT' program. The results show that teachers perceive horizontal and vertical factors to enhance CIP. Furthermore, especially school principals and coach-teachers seem to be able to strengthen horizontal and vertical factors which leads to more CIP. We discuss implications for research and schools in the Netherlands and beyond.