In this paper we addressed the role of motivation in stimulating school success. We analyzed the concept of motivation, through the multitude of definitions proposed by the literature. Motivation is an essential condition for the student's success in school work. Motivation underpins a coherent, consistent and long-lasting learning process. Ideally, extrinsic motivation, with maturation and growth of school and social experience, is transformed into intrinsic motivation. Moreover, the instructional-educational process must be designed in such a way as to provide the student with learning motivations appropriate to his or her level of development. Only in this way can motivation constitute a real "engine" of learning and, by implication, of development.