The paper gives an overview of multidimensional adaptive testing (MAT) and evaluates its applicability in educational and psychological testing. The approach of Segall (1996) is described as a general framework for MAT. The main advantage of MAT is its capability to increase measurement efficiency. In simulation studies conceptualizing situations typical to large scale assessments, the number of presented items was reduced by MAT by about 30-50% compared to unidimensional adaptive testing and by about 70% compared to fixed item testing holding measurement precision constant. Empirical results underline these findings. Before MAT is used routinely some open questions should be answered first. After that, MAT represents a very promising approach to highly efficient simultaneous testing of multiple competencies.