This article reports on a systematic review of the Self-Study of Teacher Education Practices research literature published between 1990 and 2012. Self-study research refers to teacher educators researching their practice with the purpose of improving it, making explicit and validating their professional expertise and, at the same time, contributing to the knowledge base of teacher education. Reflecting our analysis, we defined self-study as a research approach in the field of teacher education which can be typified by the following characteristics: self-study research focuses on one's own practice; for this reason, it privileges the use of qualitative research methods; collaborative interactions play a central role in the research process; and its validation is based on trustworthiness. Furthermore, we identified two tensions inherent in the self-study work, on which researchers always and continuously need to position themselves for self-study inquiries to achieve its purposes: the tension between relevance and rigour on the one hand, and that of effectiveness and understanding on the other hand.