Peer learning offers powerful spaces for teachers to reconsider beliefs and change practice. Although productive teacher collaborations have been identified, there are few descriptive accounts explaining the detail of these collaborations and specifying conditions that enabled teachers to learn from each other. This article explores the ways in which two secondary school science teachers used the framework of an action research project to take a language focus in the teaching of science. This joint work involving devising, implementing and evaluating a work plan, enabled them to challenge their beliefs and practices. Insights into requisite conditions and the dilemmas experienced for any collaboration leading to teacher change in beliefs and practices when bringing a specific language focus to their science teaching are explored.