In the present work, published experimental information has been evaluated to produce a self-consistent set of thermodynamic and phase diagram data for the Sn-Zr system. The thermodynamic evaluation for all stable phases is obtained by using the CALPHAD method. The calculated phase diagram and thermochemical properties are compared with the experimental data. Most of the available experimental data are satisfactorily accounted for by the present thermodynamic description. The need for new experimental work on the solid/solid transformation in the middle and on the Sn-rich side of the system is emphasised.