• Accurate measurements of the surface tension of liquid Fe-Ni, Fe-Cr, and Ni-Cr using electromagnetic levitation. • A generalized parametric model was developed to predict the surface tension of binary alloys under the influence of oxygen. • The developed statistical model was successfully applied to predict the surface tension of liquid Fe-Ni-O. Surface tensions of liquid Fe-Ni, Fe-Cr, and Ni-Cr were measured by oscillating droplet method using the electromagnetic levitation technique. The measurements were performed in gas atmosphere of Ar-5% H 2 or Ar, where the resulting oxygen contents of the samples are less than 0.003 at.% and 0.03–0.10 at.%, respectively. The influence of oxygen on the surface tension is demonstrated to be significant, and the decrease in surface tension strongly depends on the oxygen contents and temperature. A Langmuir-based oxygen adsorption model for binary alloys was developed from a physics-informed statistical approach considering the distribution of oxygen allocation in different elements, which statistically predicts and physically interprets the oxygen-induced surface tension shift in binary alloy melts. This generalized parametric model was successfully applied to liquid Fe-Ni-O and showed a good agreement with the experimental data and the Butler model.