The proposed study focuses on the dynamics of students’ motivation and their influence on academic results. The purpose of the investigation is threefold: to study the changes in students’ motivation over one academic semester; to investigate if there are different types of students, according to the patterns of motivational dynamics they experience; and to study if such patterns influence students’ subjective and objective performance. Such information is undoubtedly of great interest to teachers, since it provides clues as to improve the quality of students’ learning process and their results. The study is grounded in two of the most reputed intrinsic motivation approaches – the flow theory and the self-determination theory, dealing with concepts of flow preconditions, flow experience itself, perceived competence and intrinsic motivation. What is more, motivation is considered a dynamic, non-ergodic process what is an important contribution to previous research in the field. The data were collected longitudinally, ten times during the semester. Participants were 291 university students, with a total of 2110 filled questionnaires collected. Data analysis was conducted using R software, descriptive statistics, graph procedures, multivariate latent process mixed models and comparison of means were applied. The main findings confirm that students experience the dynamics of motivation over time and that they can be grouped according different patterns of this dynamics. Moreover, those whose motivation increases over semester tend to achieve better performance, compared with students whose motivation is stable or decreases. Implications of the results are discussed.