Despite the large number of its different forms of manifestation and of handling, dropout has so far received comparatively little attention in research on adult education. There is only a small number of theoretical concepts that systematize the diverse interpretations of the phenomenon within a superordinate framework. This study aims at contributing to that question. To that end, theoretical concepts of dropout in further education and approaches to an interpretation of dropout from further education as a further-education-specific behavior are collated and the research gaps with regard to a comprehensive model explaining the reasons for dropping out from further education are revealed. By referring to an empirical study—based on the evaluation of 40 problem-centered interviews—a typology as well as a model for the characterization of dropout cases is proposed and its potential for further theory building in this field is explored. Through this approach, the central concept of “fit” emerges, which allows to describe the variety of dropout constellations in a theoretically compatible way.