The study presents the collaborative reflection process of a teacher educator and two elementary teacher candidates during their university mathematics teaching class and subsequent student teaching experiences. This self-study paid particular attention to the unforeseen negativity created in the practice of teaching as a starting point for reflective thinking and how it eventually led to a renewed level of teaching practice and thinking. This collaborative self-study provided an opportunity for each researcher to notice the differences between her intention for practice and her actual practice, from her own perspective as well as those of others, working with a view of teaching as disciplined inquiry. The authors conclude that the results suggest that collaborative self-study by a teacher educator and teacher candidates can generate effective learning experiences for all participants.