The purpose of this paper is to develop a dynamic sliding mode control (DSMC) for a two-input two-output (TITO) temperature system. First, the interaction between variables is analysed using the relative gains matrix (RGA) and the Bristol criterion to design a decoupler scheme. After that, a DSMC control scheme for the TITO system is then proposed using a decoupler; in addition, the proposed controller is tuned using the mean-variance mapping optimisation (MVMO) method. Next, experimental tests of reference changes, parametric uncertainties, and experimental disturbances are performed on the Temperature Control Lab (TCLab). Finally, the performance of the proposed controller is compared against a PI controller and an SMC using TVu, ISE, and IAE performance indices, where it is shown that the proposed controller can reduce the chattering effect for the TITO system.