Teaching students how to regulate their own learning has become a popular innovative practice in primary education. However, not much is known about how teacher as well as school characteristics enhance students' self-regulated learning (SRL). This study explores whether schools differ in the way they implement SRL and what factors at the school and teacher level are related to successful classroom implementation of SRL. Survey data was gathered from 331 teachers in 44 primary schools. A comprehensive theoretical model, identifying determinants on teacher and school level related to teachers' SRL implementation, was tested using structural equation modelling. Results indicate that teachers' beliefs and teacher self-efficacy are strongly related to SRL implementation. At the school level, the importance of a shared SRL vision and the engagement of teachers in reflective dialogue are highlighted with implications for the role of the school leader. Recommendations for future research and considerations for teachers' educational practice are discussed.