Purpose: The purpose of this paper is to contribute to further studies of theoretical and conceptual understanding of teachers' team learning processes, with a main focus on team work, team atmosphere, and collective reflections. Design/methodology/approach: The empirical study was designed as a multi-case study in a research and development project. The case studies include three teacher teams from different schools. Data were collected though observations and in-depth interviews and analysed qualitatively. Findings: The main findings show that the teams differ with regard to collaboration and team atmosphere, and willingness to learn collectively. The analyses of talk at team meetings show the importance of collective reflection loops through which the teachers transform the contents of their conversations. A facilitating team atmosphere seems vitally important for the emergence of the identified collective reflection loops. Collective reflections potentially increase team learning. Research limitations/implications: Case study and conversation analyses which were mainly focused on verbal communication have certain limitations. A multi-case design and different methods for data collection were used to offset these presumed weaknesses. Practical implications: One of the purposes with the research and development approach was to support teachers' team learning processes. The findings provide insights and model of team learning with further practical implications for teacher teams. Originality/value: The findings show that a facilitating team atmosphere supports collective reflection loops, with potential to increase the team's collective competence. These findings provide valuable contributions to further conceptual understanding of team learning. (Contains 2 tables and 1 figure.)