This book provides a decolonial critique of dominant global agendas concerning teacher professionalism and proposes a new understanding based on UNESCO-funded research with teachers based in Colombia, Ethiopia (Tigray), India, Rwanda and Tanzania. It opens by outlining dominant conceptions of teacher professionalism as they appear in the global literature. It then introduces Ndlovu-Gatsheni’s (2013) three dimensions of coloniality, namely, the coloniality of power, of knowledge and of being, as a framework for considering the effects of the colonial legacy on teacher professionalism and setting out the teachers’ ideas concerning the barriers and affordances to their professionalism. This provides a basis for outlining the teachers’ perspectives on how teacher professionalism may be conceptualised, which is discussed in relation to existing global narratives/conceptions. The main arguments advanced in this book are that a decolonial lens is helpful for contextualising the perspectives of teachers in the global South; the lived experiences and material conditions of these teachers are often neglected in dominant discourses; the importance of situating the perspectives of teachers in an understanding of local contexts and realities; and, that in contrast to deficit discourses that predominate in the global literature, there is much that can be learned about teacher professionalism from teachers in the global South.