Evidence on the impact of second language teacher education is inconclusive in the area of pronunciation pedagogy. This study explores how the cognition (knowledge, beliefs, thoughts, attitudes and perceptions) of 10 pre-service and five in-service teachers developed during a postgraduate course on pronunciation pedagogy. Questionnaire items, focus group meetings, semi-structured interviews, classroom observations and an assessment task were used to trace the development of participants' beliefs and knowledge. Findings demonstrated that the development of the student teachers' cognition was limited and the notion of integrating pronunciation into L2 lessons proved to be challenging for participants irrespective of their pronunciation teaching background. Also, while student teachers' awareness about the benefits of kinesthetic/tactile teaching techniques increased, native English-speaking teachers without any pronunciation teaching experience appeared to be particularly susceptible to factors restricting cognition development. The paper concludes with a discussion about implications for language teacher educators preparing pronunciation instructors.