Large eddy simulations are carried out to predict the flow noise produced in the solenoid valve of an antilock braking system (ABS) using Lighthill’s acoustic analogy and the Ffowcs Williams and Hawkings (FW–H) surface integral method. The fluid inside the valve is assumed to be incompressible at a fixed temperature. The solenoid valve operation is realized by applying an overset grid methodology to the moving plunger, and the plunger has a linear motion in the axial direction. Several types of solenoid valves are numerically designed to maximally reduce the flow noise. The upstream flow is detached through a small opening between the plunger and the seat, which generates pressure fluctuation around the narrow gap, which is subject to high wall pressure fluctuations and shear stresses. Large eddy simulations are performed by varying the position of the flow separation. An optimal design of the valve is obtained, featuring a small radius of surface curvature, a smooth surface, and a large plunger tip area angle. Measurements are obtained from the optimal design to validate the design in a real vehicle performance test, and the predicted pressure frequency in the solenoid valve agreed well with the experimental results.