Continuous reflection on instruction is one of the protocol axes of differentiated instruction, training and implementation. Reflective practices facilitated teachers’ professional development and helped toward the promotion of self-awareness regarding their practices and the impact these had on their students, whilst determining their needs for more and particular professional development (Beauchamp & Thomas, 2009). Throughout the study, teachers had the opportunity to work and cooperate not only with the trainer/researcher, but also with colleagues from their schools or neighboring schools, for the preparation of material and the implementation of differentiation. Teachers presented the course of their work with emphasis on practices that were well employed and found to be effective. They discussed problems or obstacles they had encountered in their effort to differentiate their instruction on a daily basis. Furthermore, the researcher observed and/or co-taught lessons in order to help teachers understand some of the differentiated instruction strategies and therefore, overcome any particular difficulties teachers had encountered at the time. The researcher had also the opportunity to observe differentiated lessons, by using the differentiated instruction’s observation protocol that was created for the needs of this study. After the lesson, the teacher and the researcher had time to discuss and reflect on the lesson, utilizing specific observation criteria. Collaboration between the trainees and the researcher was also established through a website, particularly developed for this study and an online forum in which teachers could have constant communication with the researcher and other teachers participating in the study. Teachers used the forum to share ideas, educational material, and problems or difficulties they were facing.