The literature on mismatch considers the so-called ‘overeducated’ mostly as a homogeneous category and does not consider the match between subject and job content. In this article we distinguish between the overeducated with a horizontal match and those without a horizontal match. Our starting hypothesis is that being overeducated without realizing a horizontal match is especially problematic. Our results, based on data for higher education graduates in Flanders, are consistent with this. We find that the negative effect of being overeducated is stronger for youngsters without a horizontal match. We also find that both types of overeducation are connected to different mechanisms. The regional unemployment rate, for instance, mainly explains overeducation with horizontal match. Both types of overeducation, even if not in the same way, are also influenced by the quality of human capital as well as the subject of study.