Superconducting films of Ag-doped Tl–Ba–Ca–Cu–O with a varying molar ratio of Ag dopant ranging from 0 to 0.5 were prepared by spray pyrolysis of Ba–Ca–Cu–Ag–O precursor films on MgO substrate, and then post annealed with Tl-bulk sources. Phase transformation of the multiple phases of Tl-2212 and Tl-1223 to a single-phase of Tl-2223 was observed in the Ag-doped Tl–Ba–Ca–Cu–O superconducting films annealed at temperatures close to the melting point, 885°C. The critical transition temperature (T c,R=0 ) increased and electrical resistivity decreased as the dopant concentration increased up to 0.5. Doping effect of Ag in the Tl-based film not only improves the critical transition temperature and current density but also facilitates the formation of single-phase Tl-2223 at lower temperature. Critical transition temperature (T c,zero ) and current density (J c , 77K, 0T) of the best resultant Tl-based film were shown to be 123K and 5.7×10 4 A/cm 2 , respectively.