An embedded-atom type potential for liquid indium is developed by fitting bulk liquid thermodynamic and structural data. An empirical pairwise Ar-In interaction is also proposed. Molecular-dynamics simulations of argon scattering from liquid indium are carried out and compared with molecular beam scattering data. Very good agreement is found between the experimental and theoretical angular and energy scattering distributions. This supports the potential functions used. Implications for the atomic-scale structure of liquid In and for gas-surface energy transfer are briefly discussed.