The theoretical frameworks presented in this Special Issue are appraised with respect to how they might enhance teachers' or researchers' work with "special needs" students learning mathematics. The notion of "special needs" is used in a broad sense, encompassing specific Special Educational Needs as well as students with low attainment. The analysis indicates that the different frameworks offer some distinctive methods for research or ideas for interventions, either individually or within multi-lens approaches. It also points to other perspectives, not represented here, that could be relevant for a growing understanding of issues of affect in mathematics education.