In this paper, the effect of a thin interlayer of Pt on thermal stability of NiSi films on Si(111) has been studied. The Ni/Pt/Si(111) bilayered samples with the same film thickness were annealed by rapid thermal annealing at 640 °C-900 °C. Both the X-ray diffraction analysis and four-probe measurements show a remarkable improvement in the thermal stability NiSi as a result of Pt interlayer. The possible reason for the enhanced NiSi thermal stability is attributed to the formation of the Ni(Pt)Si solid solution and its preferred orientation, leading to the decrease in the driving force of NiSi2 nucleation and the increase in the interfacial energy change respectively. The experimental results are explained in terms of Miedema’s Model and Thomas-Fermi-Dirac (TFD) equations in detail.