The DiDeSu project aimed to empower teachers develop focused interventions in terms of instructional methodology in order to help all students to improve and experience happiness and success. In particular, the project aimed to promote teachers professional development that would lead teachers in acquiring the necessary skills and knowledge to effectively apply differentiated instruction, thus being able to respond to the needs of all students in mixed ability classrooms. Furthermore, the project promoted and supported the establishment of an ethos of collaboration within every individual participating teacher enabling them to rely on their own knowledge and expertise, to apply peer coaching practices, to jointly design lessons, to develop instructional material, to observe lessons of their colleagues,to evaluate, to reflect and to improve their practices. The DiDeSu moodle learning platform also provided opportunities for collaboration between teachers from other schools and different areas and from all participating countries the. The outcomes of the project will be accessible not only to the participating institutions, but to anyone interested in the topic via the utilization of contemporary ICT tools, like web-pages, discussion forums and e-classes.Based on the above, the specific objectives of the project were:1) To provide training and support to teachers (primary school) in order to apply differentiated instruction.2) To develop school based training schemes, based on peer coaching approaches. 3) To create on-line tools that enhances collaboration, communication and exchange of good practices. The main outcomes of the project included the design and delivery of two teacher training courses on the topics of differentiation of instruction and lesson observation/evaluation/feedback (2 series of seminars each consisting of 15 instructional hours to be offered twice in each participating country). These seminars were delivered in all the participating countries in the mother tongue of the participants. Teacher trainers who delivered these seminars were trained in advance by distinguished scholars/researchers (2 seminars, one on differentiation and one on lesson observation/evaluation/feedback,each having a 5 day duration). Teachers were constantly supported by the experienced trainers throughout the duration of the project: teacher trainers visited teachers at schools to help them design lessons, to observe their instructional practices and provide constructive feedback and even organize co-teaching sessions. All the material prepared by the teachers and their trainers were uploaded on a web platform, an e-class accessible to all the participants and also were opened to anyone else interested in the topics at hand. The e-class supported material in the language of the participating countries, as well as material in English (some key aspects of the work was translated into English in addition to some key readings about differentiation and lesson observation). Further to the e-class, a book was prepared in English to disseminate the good practices that emerged in the course of the project. The potential long term benefits of the project were that the project helped in the development of practices of teacher training that continues to be implemented after the completion of the project.