The guidance law design for the missile–target interception problem in the presence of system uncertainty is investigated in this paper. To improve the disturbance rejection property, two kinds of non-smooth guidance laws based on a finite-time control technique are developed. The first is a high-gain finite-time guidance law, which can be derived by assuming that the system uncertainty is bounded by a constant. The second one is a composite guidance law including a disturbance observer and a finite-time state feedback, where the disturbance observer is introduced to estimate the system uncertainty and the finite-time state feedback is to stabilize the guidance system. Under both of the proposed guidance laws, it can be proved that the line-of-sight angle rate will converge to the origin or a small region of the origin in a finite time. Simulation comparisons show the effectiveness of the proposed method.