This paper discusses the aims and challenges of inclusive mathematics instruction and presents data from a video study of 34 inclusive classrooms. Criteria for inclusive mathematics instruction are identified, and a conceptual framework is presented with a particular focus on very heterogeneous groups of learners that include students with intellectual disabilities. Key issues with the inclusive approach are the need to adapt learning goals (differentiation) and to manage joint learning settings. Data from the study show a rather limited use of differentiated learning goals in general and for students with intellectual disabilities in particular during inclusive mathematics instruction. Correlation analyses reveal that, in the classrooms studied, there was either a focus on differentiated learning goals or a focus on joint learning situations. The simultaneous implementation of both differentiated learning goals and joint learning settings seems to be very challenging in inclusive teaching settings. Therefore, teachers must be given specific support aimed at enabling them to meet this challenge.