This article summarizes recent research regarding the importance and impact of collaborative practices, with a particular focus on the role of school leaders in international schools. The authors outline reasons why collaboration is essential to support multilingual learners, including facilitation of students’ language development and their academic achievement and its positive impact on teachers’ professional learning. The article includes a table which describes practical actions that teachers and leaders can do throughout the four different stages of the collaborative cycle: collaborative planning, co-teaching, collaborative assessment and collaborative reflection.