Magnetorheological dampers have raised as promising devices for structural seismic protection since they have many attractive features such as small power requirements, reliability, and relatively low cost. These devices have strongly nonlinear behaviour which is very difficult to characterize. For this reason, the modelling of MR dampers has been an active field during the last years and has produced several models by combining a physical insight with a black-box approach. Among them, the so called “viscous + Dahl model” has been introduced as a particular case of the normalized version of the Bouc-Wen. Viscous + Dahl model is indeed significantly simpler than some other approaches and has well established conditions to ensure its physical and mathematical consistency. This work deals with the modelling and identification of a small scale MR damper which is described by the viscous + Dahl model. The obtained model is validated experimentally into a real time hybrid test (RTHT) configuration where the MR damper is working as the seismic protection of a civil structure. The results show a good match between experimental and predicted forces.