This article reviews recent research on teachers' professional identity, highlighting three categories of studies: (1) studies on the formation of teachers' professional identity, (2) studies on the characteristics of teachers' professional identity, and (3) studies that use teachers' stories to represent professional identity. The concept of professional identity is defined differently or not defined at all in the studies. Four essential features of teachers' professional identity are identified: (1) it is an ongoing process of interpretation and re-interpretation of experiences, (2) it involves both person and context, (3) it consists of sub-identities that more or less harmonize, and (4) agency is an important element of professional identity. The studies reviewed show that professional identity is not fixed but dynamic and influenced by various factors, including personal experiences, social contexts, and educational theories. The research also emphasizes the importance of reflection, personal practical knowledge, and the role of context in shaping professional identity. The studies suggest that professional identity is formed through an ongoing process of integration of personal and professional aspects, and that it is influenced by the teacher's personal background, experiences, and the broader social and educational context. The article argues that future research on teachers' professional identity should pay more attention to the relationship between relevant concepts such as 'self' and 'identity', the role of context in professional identity formation, and research perspectives other than the cognitive one. The studies also highlight the importance of considering the teacher's biography and the influence of educational theories on professional identity. Overall, the research indicates that professional identity is a complex and dynamic phenomenon that is shaped by a variety of factors, including personal experiences, social contexts, and educational theories.This article reviews recent research on teachers' professional identity, highlighting three categories of studies: (1) studies on the formation of teachers' professional identity, (2) studies on the characteristics of teachers' professional identity, and (3) studies that use teachers' stories to represent professional identity. The concept of professional identity is defined differently or not defined at all in the studies. Four essential features of teachers' professional identity are identified: (1) it is an ongoing process of interpretation and re-interpretation of experiences, (2) it involves both person and context, (3) it consists of sub-identities that more or less harmonize, and (4) agency is an important element of professional identity. The studies reviewed show that professional identity is not fixed but dynamic and influenced by various factors, including personal experiences, social contexts, and educational theories. The research also emphasizes the importance of reflection, personal practical knowledge, and the role of context in shaping professional identity. The studies suggest that professional identity is formed through an ongoing process of integration of personal and professional aspects, and that it is influenced by the teacher's personal background, experiences, and the broader social and educational context. The article argues that future research on teachers' professional identity should pay more attention to the relationship between relevant concepts such as 'self' and 'identity', the role of context in professional identity formation, and research perspectives other than the cognitive one. The studies also highlight the importance of considering the teacher's biography and the influence of educational theories on professional identity. Overall, the research indicates that professional identity is a complex and dynamic phenomenon that is shaped by a variety of factors, including personal experiences, social contexts, and educational theories.