Teacher collaborative learning remains one of the fundamental methods of teacher professional development. Due to various factors, teachers have to be encouraged, counselled, and supported for taking part in such activities and that competence is commonly entrusted to principals. This research investigates the role of the principal in supporting teachers' participation in collaborative learning activities. The study was conducted through the mixed-method approach and the data were collected from 518 teachers and eight principals of 24 schools in Kosovo. Descriptive and inferential statistics were employed to analyze the quantitative data and the qualitative ones were explored through the thematic analysis. According to teachers' responses, principals employ a number of methods and offer teachers strong support for attending learning activities. Principals narrated that collaborative learning is a complex process and they have to apply various approaches, including authoritative, democratic, and instructional leadership styles, for maintaining a collaborative culture in their schools. They also revealed that collaborative learning takes place mainly in professional communities, mentoring pairs, and collective collaborative events, which are still implemented according to the traditional approaches. The findings show that newer and more advanced collaborative learning models are not applied in the research context. The research recommends that Kosovo schools should start utilizing other forms of collaborative learning and should modernize the current ones because they are insufficient and incompatible with contemporary requirements. Further similar research is recommended as such studies are almost inexistent in the research context.