This work develops a novel observer-based finite-time methodology to make disturbed wheeled mobile robots (WMRs)  follow a desired reference signal. With the kinematic and reference models, two decoupled systems are computed. Then, each subsystem’s control signal is split into three terms. The first part estimates the disturbances affecting the system, transforming the closed-loop system into two new second-order systems with uniformly bounded and convergent disturbance terms. Then, based on a new sliding surface and a design function, the second and third controller’s parts are employed to accomplish the trajectory tracking task despite disturbances. The proposed controller is compared against a finite-time and a feedback controller. Then, detailed numerical simulations show the outstanding performance of the novel proposal.