This paper deals with the design and verification of a nonlinear control algorithm for the Mobile Wheeled Inverted Pendulum (MWIP) systems. The algorithm is based on the second-order sliding mode control known as Super-Twisting Algorithm (STA) which is able to eliminate the “chattering” phenomenon and ensure robustness with respect to bounded disturbances. The stability of the closed-loop system can be guaranteed according to Lyapunov theorem. In order to show the effectiveness of the proposed controller, a simulation was carried out to make the basic MWIP model move at a constant speed. Additional simulation-testings considering model uncertainties and external disturbances were also provided to verify the effectiveness and robustness of the STA. Comparisons with the Sliding Mode Control (SMC) were given to demonstrate the superiorities of the STA and the results show the favorable performance of the proposed controller in terms of chattering elimination and robustness.