The aim of this thesis is to critically investigate and problematize the Swedish Teacher Unions’ use of the concept of professionalism within the political negotiation of how to ascribe meaning and contetnt to the idea of teacher professionalism within contemporary Swedish education debates. Departing from two recent educational reforms – the certification of teachers and the reformation of teacher education – and using theories from the sociology of professions coupled with an institutional approach to the study of organizations this study analyzes how the Teacher Unions construct professional projects in relation to each other as well as in relation to the reforms of the current Ministry of Education. Viewing professionalism as an institutional logic, it investigates the different strategies employed by the two Unions and considers their effects on the overall professional ambitions of Sweden’s Teacher Unions. By doing so it highlights the complexities facing occupational organizations – such as unions – as they engage in political struggles over how the meaning ascribed to concepts like professionalism is negotiated. In this sense, the Unions are to be considered institutional actors using the idea of professionalism in order to promote their own ideas of how the future development of the teaching profession may best serve the interests of their members. The study is based on analyses of public Union documents, as they are considered the best way to access the "public voice" of the two organizations. The primary material consists of referrals in which the Unions respond to the suggestions of governmentally appointed public commissions suggesting how certain political initiatives are to be realized. In addition to these formal statements, debate articles by (primarily) the Union chairs are also included in the analyses in order to provide a sense of how the Unions place their policies in relation to the overall education policy debates of Sweden. The textual analyses draw on the ideas of "policy sociology" as sociological concepts are used to interpret and understand the policies of the Unions. It is not an analysis for policy, in the sense that it is aimed at providing the Unions with strategies for how they are best to accomplish their policy objectives, but rather a critical analysis of the policies they employ and how these can be understood in the context where they arise. A central argument of the study is that the fact that Swedish teachers are organized in two different Unions complicates the formulation of a common professional project on behalf of Swedish teachers in general. This is because the two Unions, though united in their wish to turn teaching into a "proper" profession, are constructing their professional projects from opposing points of departure, resulting in a process of intraprofessional boundary work, originating from the historical tension between different teacher categories. As a result of the internal struggles between the two Teacher Unions the position of Swedish teachers in general becomes weak in relation to national educational policy makers. As the Unions are forced to compete for political influence in order to gain support for their own policies, their professional projects become dependent upon the political system in general. The overall conclusion to be drawn from the study is that the idea of teacher professionalization in the context of Swedish educational policy making is a decidedly political process, somewhat removed or de-coupled from the everyday practice of Swedish teachers. As a consequence, the Unions are, above all, using the concept of professionalism as a symbolic resource by which to create legitimacy for their efforts of increasing the social status of teaching in society.