Purpose: In organisational and innovation research, the term “open innovation” refers to the inflow and outflow of knowledge to and from organisations: with open innovation theory suggesting active exchanges of knowledge with external actors leads to the development of exploitable new ideas. In the field of education, however, the exchange of knowledge with external parties represents a paradigm shift. In response, this article presents findings from research design to explore the nature and composition of school innovation networks, and the effects of such these networks on knowledge mobilisation. Design/methodology/approach: The study draws on data from a representative random sample of 411 German school leaders. Respondents were asked to detail their engagement in open and closed innovation activity and their school's external collaborations during the last 12 months. A latent class distal outcome model was developed to examine whether different types of collaboration associate with different knowledge mobilisation processes. Findings: The study findings suggest that schools in Germany mainly use internal knowledge for innovation, with external knowledge exchange taking place on a very limited basis. Knowledge mobilisation varies depending on the innovation network. The authors use the findings to indicate new insights for how schools can further innovate learning and teaching in future. Originality/value: Although there is increasing discussion on Professional Learning Networks in schools, the discourse on knowledge mobilisation within educational networks is limited, making concept of open innovation so far completely absent from discourses on school improvement. This paper initiates the population of this new research space.