The phase equilibria and thermodynamic properties of the Pd–Sn and Pt–Sn alloys have been studied intensively due to the importance of these systems for microelectronics, dentistry, and jewelry. In this work, the thermodynamic and phase diagram data of the Pd–Sn system and the Pt–Sn system available in the literature were critically reviewed, thermodynamic assessments of the entire Pd–Sn and Pt–Sn systems were then carried out based on the critically evaluated literature experimental information and the previous thermodynamic modeling work. The liquid phase of both systems was described using the modified quasi-chemical model in pair approximation. A set of self-consistent thermodynamic description for each system was reported, which can generally reproduce most of the reliable thermochemistry and phase equilibria data in the literature. A comparative study of different solution models in describing liquid with strong short-range ordering was also presented.