The basic functionality of the spillway is to control the flow and safely convey the excess flow while keeping the structure stable. An ogee spillway is commonly used due to its high discharging capacity. The discharge coefficient of an ogee spillway is greatly affected by the ratio of an operating head and design head. Since physical models are expensive and have limitations in terms of scale effect, a comprehensive numerical simulation was performed in this study to estimate the discharge coefficient for an ogee spillway under various head ratios using CFD-based numerical modeling. The numerical simulations were done using FLOW-3D. In the present study, renormalized group (RNG) �� − �� turbulence closure model and the Volume of Fluid (VOF) algorithm were used for the simulation of flow over an ogee spillway. The discharge coefficient of the ogee spillway computed using CFD simulation for various head ratios shows a reasonable agreement with the values reported in the literature. Also, the water surface profiles, pressure distribution, discharge rating curve, and velocity distribution over the ogee spillway for the different heads were plotted and analyzed.