Labyrinth spillway has become an appropriate choice to increase an existing spillway’s capacity.  Thus, it is necessary to understand the hydraulic performance of labyrinth spillways/weirs. This  paper numerically solves turbulent flow over labyrinth spillways/weirs and determines the  discharge coefficients. Reynolds governing equations, turbulence k-ε model, and the volume of  fluid (VOF) model are numerically solved to define pressure, velocity, and the free surface flow  profiles. The numerical results are comparable to those obtained from physical modeling with  maximum 6.43% error relative to results of physical modeling. Present study indicates that numerical simulation can be used to supplement physical modeling. Thus, by using numerical  solutions the site specifics of the spillway which are often different from the conditions of design  curves can be investigated. Also, the effect of different shapes of apex on discharge capacity of  the labyrinth spillway is investigated in this study. The analyses show that labyrinth spillways  with round apex shape are the most efficient spillways. Numerical determination of free water surface is presented and discussed, which is helpful for optimum design of stilling basin and leading walls.