This article shows the research results of implementing a professional learning model based on instructional leadership practices and structured teacher collaboration. The primary purpose was to promote a collaboration model focused on developing communities of practice, formed by school leaders and teachers, focusing on instructional improvement in 8th grade Math and English. The model consists of a cycle with 4 iterative practices: planning, classroom observation, feedback, and refinement and three guiding principles: deprivatisation, collaboration, focus on learning. The methodological approach was a design-based research model, with school teams (within-school level) and collaboration networks (between schools-level) that included principals and teachers. 22 schools in two districts in Chile, 44 school leaders, 74 teachers, 49 non-participating teachers as a control group, and at least 1,000 students in 40 classes were part of the study sample that participated in the research between 2019 and 2020. Mixed methods were used for data analysis. The research team conducted a five-scale questionnaire and semi-structured interviews with participants and nonparticipants teachers as the control group. The main progress was the deprivatisation of pedagogical practice and joint decision-making for teaching improvement. The practical implications of the model, adjusted for local characteristics, are that it facilitates professional development at three levels: individual, within school teams, and allows professional exchange between schools. It enabled the enactment of peer collaboration practices, and the role of instructional leadership shared between teachers and the school leadership team members were bolstered.