The notion of teacher training has been conceived in different ways over time, ranging from the idea of training to current conceptions of a broader and more continuous process. We know that this training must include the development of a competent reflective practice through learning that takes place in practical situations that take into account the context in which educational practices are inserted, becoming the possibility of creating spaces for participation, reflection and training. From this perspective, teacher professional development is seen as a process that involves not only initial and continuing training, but also different ways of working that promote the exchange of experiences, the sharing of knowledge between teachers and consolidate spaces for mutual training. In this sense, collaboration has proved particularly important. In this paper we aim to investigate the conceptions of teacher training and professional development in the context of a collaborative project in order to answer the following question: How and in what aspects can a university-school collaborative project contribute to the Professional Development of Teachers?