A Monte Carlo simulation is used to calculate the pair distribution function g(2)(r1,r2) for a planar gas–liquid interface. Due to the cylindrical symmetry of the system, g(2) can be stored as a three-dimensional array that can be readily manipulated and used to calculate the surface tension and the single atom density profile directly. The consistency and accuracy of our calculation of g(2)(r1, r2) is demonstrated by a calculation of the single atom density through the first Born–Green–Yvon equation. We show that the surface tension calculated directly from the pair distribution function and from other well–established routes is completely consistent. In the case of the gas-liquid interface for argon modeled with an explicit inclusion of the three-body forces, an accurate pair distribution can be used to estimate the long-range contribution to the three–body part of the surface tension. A detailed analysis of this correction, its dependence on the three–body cutoff, and its overall contribution to the surface tension are presented.