Over the past few decades, increasing more research has examined the cognitions (knowledge and beliefs) of second language (L2) teachers. Such research has provided insight into what constitutes teachers' beliefs and knowledge about teaching, how these cognitions have developed and how they are reflected in classroom practice (see Borg, 2006). Although numerous studies have been conducted into the curricular areas of grammar and, to a lesser extent, reading and writing, even fewer have examined teachers' cognitions into pronunciation instruction. The purpose of the present study, therefore, is to explore some of the dynamic relationships that exist between L2 teachers‘ cognitions and their actual pedagogical practices, but with a specific focus on how these cognitions have developed over time. In particular, the cognitions and practices - as they relate to the teaching of pronunciation - of five experienced ESL teachers are investigated. Overall, findings reveal that the amount of training teachers have received in pronunciation pedagogy strongly affects not only their knowledge of pronunciation and pronunciation pedagogy, but also their confidence in that area. Results further show that L2 learning experiences, teaching experience and collaborative work with colleagues can also influence teachers' practices and cognitions.