In this paper, comprehensive experimental and simulation studies were conducted to determine the optimum combination of seat and ball for actual gas lift valve (GLV). The experiments were run for multiple ball and seat sizes to cover the whole gamut of industrially used GLVs. A numerical model, built based on computational fluid dynamics (CFD), was validated first using experimental results. The difference between experimental and simulation runs for multiple cases was found to be maximum 5%. Finally, results from both simulations and experiments were utilized to determine the optimum seat and ball geometries. From the actual GLV experiments and the simulations, it was concluded that the optimum port top diameter (PTD) of the seat is 2/16-inch larger than the port bottom diameter (PBD) when used in combination with a ball that is 1/16-inch larger in dimeter than the PBD. It was also concluded that, with the aforementioned optimum combination of the ball and the seat, the entirely beveled seats perform better than both the partially beveled seats and the sharp edge seats. This optimum combination of the ball and the seat resulted in a GLV gas throughput improvement of more than 27% over the currently used design in the industry for 5/16-inch port seat. For larger port seats, this improvement is expected to be even greater.