Using molecular simulations the interaction between a noncharged nanoparticle and an ideal liquid-liquid interface is studied. The free energy profile as function of nanoparticle-interface separation is determined using Wang-Landau sampling. Comparison between the simulation results and macroscopic theories shows that the latter give a poor description of the free energy profile. In particular, they underestimate both the range of interaction between the particle and the interface and its strength, with the discrepancy lessening as the particle radius increases. On increasing the solvent chemical potential the interaction strength increases and the interaction range decreases due to the increase in interfacial tension and consequent decrease in interfacial width.