Magnetorheological elastomers based on the combination of a polymeric matrix with magnetic fillers allow the possibility of controlling their mechanical properties when an external magnetic field is applied. This so‐called magnetorheological effect can be exploited for a variety of applications. Herein, a comprehensive outlook at the state of the art is provided, in terms of the materials, effects, and applications. The physical effects that result in the magnetorheological effect are described, both from a micro and phenomenological points of view. Then, the possible combinations of different polymeric matrices and magnetic fillers, along with other additives, are presented, allowing to tune the mechanical properties, mainly dependent on the polymer matrix, and the magnetic field response, which is related to the magnetic filler. Finally, representative applications of magnetorheological elastomers are presented. This review represents an up‐to‐date state‐of‐the‐art in the field of magnetorheological elastomers as a ground to highlight the main achievements and point the specific needs to improve their response and applicability by further tuning materials and configurations.