Providing contingent or adaptive support (i.e., scaffolding) is effective. Yet it is unclear how it promotes students' learning. In this mixed-methods study, we investigated to what extent the effect of contingent support for students' learning is mediated by the extent to which students take up teachers' support in subsequent small-group work. We define contingent support as support that contains adapted levels of teacher control or regulation based on the learner's level of understanding. To explore the research question, we analyzed all interactions from 35 lessons of 7 secondary social studies teachers and 7 small groups of students. Logistic multilevel mediation analyses showed that the likelihood of students formulating accurate answers during small-group work was higher when students applied the teacher's support in subsequent small-group work (as opposed to ignoring that support). However, the contingency of a teacher's support did not affect students' uptake or the accuracy of their answers. Additional qualitative analyses showed that students' uptake of contingent support was sometimes hampered by untimely fading of the support. Moreover, we found that contingent support that was then gradually faded was the most effective in fostering students' uptake of a teacher's support.