This paper addresses the following questions: how do students perform metacognitive, cognitive and affective learning functions; how is the execution of learning functions regulated by internal and external sources; what learning styles can be discerned from the viewpoint of learning functions and regulation? Subjects were students from an open distance university and a regular university. They were interviewed extensively about their learning strategies, mental models of learning, learning orientations and interpretations and appraisals of instructional measures. The interviews were analyzed in a phenomenographic way. The results indicate that there are large differences among students in the manner in which they carry out learning functions, that these differences are associated with internal and external sources, and that four qualitatively different learning styles can be discerned: an undirected, a reproduction directed, a meaning directed and an application directed learning style. Mental models of learning and learning orientations turn out to be related to the way in which students interpret, appraise and use instructional measures to regulate their learning activities. It is concluded that in many instances instructional measures do not have the intended effects. Suggestions are given regarding the implications of these results for the improvement of teaching practices in higher education.