This investigation has been focused on the spray-deposited pure cadmium oxide (CdO) thin films and also doped with zinc (Zn) and tin (Sn), as a transparent conducting oxide for optoelectronic applications. By varying the concentration of Sn (0–2%) into CdO, the microstructural, morphological, and optoelectronic properties were investigated. XRD spectra confirmed the polycrystalline cubic structure of the pure, doped, and co-doped CdO films. SEM investigation reveals the crack-free homogeneous cauliflowers-like morphology of the fabricated thin films. The existence of elemental compositions such as Cd, Zn, Sn, and O in the prepared films was confirmed by EDS analysis. All of the doped and co-doped CdO films showed good transparency in the visible range. Moreover, a slight increment has been found in the optical band gap from 2.43 eV to 2.50 eV with increasing Sn concentration, which can be explained by the Burstein-Moss phenomena. A decrement of Urbach energy was noted for an increased concentration of Sn. Besides, Zn and Sn (1 %) co-doped films exhibited the lowest electrical resistivity value 4.09×10−4 Ω-cm among other doped compositions. However, the addition of Zn and Sn into CdO thin films enhanced the optoelectronic properties.