Pile foundation is considered one of the most widely used deep foundation solutions for heavier structures in weak subsoil. The structural design of a pile foundation is governed by its shear, bending, and buckling behaviour. The current design code of India provides a simplified way to estimate the bending demand of the foundation by considering a hypothetical fixity point in the pile to treat it as a structural member without soil around. Similarly, the code also provides guidelines to find the effective length of the pile to determine the buckling capacity of it considering it as a structural member. However, this proposed effective length is a function of pile diameter and two types of soil (i.e., good or weak), without considering the possible large variability in the soil strength and stiffness. During seismic events, if the subsoil undergoes liquefaction, the soil loses its strength and stiffness significantly. On the contrary, when the liquefied soil undergoes large strain due to large pile-soil displacement, the strength and stiffness increase again. Also, during an earthquake, the foundation is subjected to both inertial load from the superstructure mass and kinematic load from the surrounding soil, which, in turn, affects the strength and stiffness of the soil. Therefore, during an earthquake, both the structural demand and structural capacity of the pile for both bending and buckling behaviour change. Due to liquefaction, the pile foundation becomes largely unsupported in the lateral direction and its moment demand could increase due to the secondary effect (p-delta effect), as it often becomes a long column. Also, the buckling capacity greatly reduces due to any increase in its unsupported length. Therefore, estimating the appropriate effective length to treat it as a structural element within soil becomes important not only for evaluating the correct bending moment demand in the pile but also for determining its buckling capacity appropriately. The present study, therefore, aims to estimate the buckling capacity of the pile foundation in a liquefiable soil deposit. Here, a numerical model has been developed considering non-linear pile-soil interaction and liquefaction of the surrounding soil. Two cases of pile foundation have been analysed which are embedded in, (a) non-liquefiable deposit and (b) liquefiable deposit. The stiffness of soil has also varied and the buckling capacity of the pile has been evaluated.