Piles are frequently built on sloping ground, particularly to provide support for bridge piers in the earthquake-prone Himalayan areas. Over the last decade, we have witnessed several earthquakes, including the devastating Nepal earthquake in 2015. Analyzing the seismic response of the pile foundation in sloping ground, taking into account soil-pile interaction, is a very intricate process. Therefore, this work aims to utilize a 3D numerical analysis to estimate the lateral load capacity of a single pile placed in sloping ground composed of cohesionless soil (dense sand with a relative density of 81%). The findings of this analysis will provide valuable insights for the seismic design of pile foundations. The numerical study was conducted using PLAXIS 3D, a software package that employs the 3D finite element approach. The Mohr–Coulomb model has been employed to simulate the stress-strain behavior of cohesionless soil. The numerical model was first validated through experimental study. Subsequently, the impact of different parameters such as slope inclination, length-to-diameter ratio of the pile, and the distance between the pile and the crest of the slope (embedded location of the pile) on the lateral load-carrying capacity and the maximum bending moment in the pile was investigated. The study reveals that an increase in slope inclination results in a decrease in lateral load capacity, but an increase in edge distance results in an increase in lateral load capacity. Furthermore, this work investigates the alteration in the lateral load capacity when subjected to a vertical force. The findings indicate that the introduction of a vertical load leads to an enhancement in both the lateral load capacity and the maximum bending moment in the pile.