The primary purpose of this paper is to investigate the response time of magnetorheological (MR) dampers and the effect of operating parameters. Rapid response time is desired for all real-time control applications. In this experimental study, a commercially available MR damper was tested and the response time was found for various operating conditions. The parameters considered include operating current, piston velocity, and system compliance. The authors define the response time as the time required to transition from the initial state to 63.2% of the final state, or one time constant. Using a triangle wave to maintain constant velocity across the damper, various operating currents ranging from 0.5 Amps to 2 Amps were applied and the resulting force was recorded. The results show that, for a given velocity, the response time remains constant as the operating current varies, indicating that the response time is not a function of the applied current. To evaluate the effect of piston velocity on response time, velocities ranging from 0.1 in/s to 3 in/s were tested. The results show that the response time decreases exponentially as the velocity increases, converging on some final value. Further analysis revealed that this result is an artifact of the compliance in the system. To confirm this, a series of tests were conducted in which the compliance of the system was artificially altered. The results of the compliance study indicate that compliance has a significant effect on the response time of the damper.