The aim of this study was to examine the characteristics of teacher education that were more likely, or less likely, to influence teachers' beliefs. The participants were five university English teachers in Mexico, and the study adopted a qualitative "life history" approach in order to elicit a wide range of experiences from each participant. The methods included a series of extended interviews and a timeline task. Five characteristics of teacher education that had an influence on teachers' beliefs were identified: length of course, opportunities for real practice, opportunities for constructivist teacher learning, opportunities for immersion in new practices, and opportunities for contextually appropriate reflection. Conversely, teacher education courses that did not influence teachers' beliefs were overly short in duration, focused on theory and transmission of knowledge, lacked modelling of desired approaches, and were disconnected from real contexts. The findings of the study may inform the planning of future teacher education courses that aims to have an impact on teachers' beliefs as well as on their practices.