This article reports on the professional benefits of using Critical Friends Group discussion protocols within a Collaborative Action Research project facilitated by two teacher-educators with four junior secondary school teachers in New Zealand. The teachers were encouraged to conduct Action Research projects on topics of their own choice. Critical Friends Group discussions were one of the several strategies implemented to provide for collaboration in the Action Research process. The findings highlight how Critical Friends Group protocols assisted collegial discussions by supporting the professional integrity of participants as they disclosed problems and gave peer feedback aimed at elevating the effectiveness of each other's practice. The protocols set up a safe space for the teachers to challenge assumptions and make suggestions leading to deeper thinking, pedagogically rich conversations and reflective listening. The Critical Friends Group discussions were complemented by other Action Research activities. Reviewing literature increased the pedagogical content knowledge available to the group. In-class observations supported teachers to identify professional problems for critique and pushed teachers to action ideas from Critical Friends Group discussions. The article concludes by advocating for teachers, teacher-leaders, and teacher-educators to explore using Critical Friends Group protocols because of the capacity to promote deep, collegial examination of pedagogical practices.