In this study, it was examined whether teachers' cognitive adaptive support (i.e., support that is tailored to students' understanding), as perceived by students, was associated with students' intrinsic motivation and academic achievement, and whether satisfaction of students' needs for autonomy, competence, and relatedness explain these associations. Multilevel analyses in a sample of n = 692 secondary education students from 35 classes revealed positive relations between cognitive adaptive support and students' need satisfaction and motivation, and mixed findings regarding academic achievement. Feeling competent mediated the association between cognitive adaptive support and achievement; feeling autonomous and connected to the teacher explained increases in intrinsic motivation. Although there was significant between-class variation for most adaptivity scales, within-classroom variation was larger, indicating substantial differences in perceived adaptivity within classes. Overall, the findings suggest that cognitive adaptive support is important for supporting students' psychological needs and motivation.