A modular procedure is presented to simulate moving control surfaces within an overset grid environment using the Navier–Stokes equations. Gaps are modeled by locally shearing the wing grids instead of using separate grids to model gaps. Grid movements for control surfaces are defined through a separate module, which is driven by an external grid generation tool. Results are demonstrated for a wing with a part-span control surface. Grids for the test case are determined from detailed grid sensitivity studies based on both nonoscillating and oscillating cases. Steady and, for the first time, unsteady pressures from overset grid computations are validated with wind tunnel data. This paper addresses the current needs of high-fidelity flow modeling to design advanced active-controls.