The present study comprehensively evaluates the improvement in lateral load-carrying capacity of steel pipe piles by adding steel plates (fins) at grade level. This configuration of steel fin pile foundations (SFPFs) is effective for applications where high lateral loads are encountered and rapid pile installation is advantageous. An integrated finite element analysis (FEA) was conducted. The FEA utilized an Abaqus model, first developed to account for the nonlinear soil-pile interaction, and then calibrated and validated against well-documented experimental and filed tests in the literature. The validated FEA model was subsequently used to conduct a parametric study to understand the effect of fin geometry on the load transfer mechanism and the response of SFPFs subjected to lateral loading at pile head. The behavior of SFPFs at different displacement levels and load levels was studied. The effect of the relative density of soil on the performance of SFPFs was also investigated. Based on the numerical simulation results, the optimal fin width for maximum improvement in lateral load-carrying capacity was suggested and the underlining mechanism affecting the efficiency of fins was explained.