The paper discusses the research and training experience of peer mentoring that the University of Catania has developed to improve the teaching skills of the University’s “expert” (senior) teachers. The action research concerned the training of expert figures identified to support colleagues in fostering professional development and educational innovation. The theoretical-methodological choices underpinning the background of the planned research-action path and the training model adopted are described. The various phases that have seen the realization of the experience in the University are analysed, which involved numerous teachers belonging to different subject areas.