The preparation of superconducting TlmCanBa2Cun+1Ox(m=1, 2; n=1, 2) thin films sputter‐deposited from two oxide targets using a symmetric RF diode sputtering technique are reported. Spatially resolved optical emission data suggest no significant bombardments of the growing film by energetic particles, resulting in a film composition close to that of the sputtering targets used. The superconducting properties of these films were found to depend strongly on the target composition, substrate and substrate temperature, as well as the the post‐annealing conditions used due to a substantial loss of thallium during annealing. For the films deposited on (100) MgO from Tl2Ca2Ba2Cu3Oxtargets, post annealing in a sealed quartz tube of the films wrapped in gold foils with sintered Tl2Ca2Ba2Cu3Oxpellets or powders at 895 and 870 °C routinely gave rise to single phase Tl2Ca2Ba2Cu3Oxand Tl2Ca1Ba2Cu2Oxfilms, respectively. Annealing at 895 °C with a used Tl2Ca2Ba2Cu3Oxfilms. These films are highly c‐axis textured with corresponding superconducting transition temperature of 123, 104, and 115 K, respectively.