The study reported in this paper, examines the effects of a rigorously designed introduction of Twitter in the educational process. In specific, it examines the relation between the students use of Twitter in the context of well-organized educational activities and their grades in an academic course. The results demonstrated a significant correlation between the use of Twitter by the students and their performance in the course. Moreover, it emerged that their participation on Twitter, could improve the students academic engagement and their sense of belonging to the academic community. Finally, possible effects of Twitter s use on students perceived internet self-efficacy were also examined. The findings and their implications of the study are discussed in detail.