This study investigates the optical properties of cadmium oxide (CdO) thin films before and after cesium-137 (Cs-137) gamma irradiation, deposited using the Chemical Spray Pyrolysis (CSP) method. The CdO films were synthesized on glass substrates with varying nozzle-to-substrate distances to examine the impact of this parameter on optical characteristics. The films underwent irradiation at a dose of approximately 1.2 Gy to assess changes in key optical properties, including transmittance, absorbance, energy band gap, and extinction coefficient. Results indicate that irradiation significantly enhanced optical transmittance across all deposition distances, with values rising by up to 2.6% at 760 nm. The optical band gap narrowed post-irradiation, ranging from 2.224 eV to 2.498 eV, suggesting improved electronic properties for applications in optoelectronic devices. Additionally, the distance between the nozzle and substrate influenced film morphology, with longer distances leading to improved transmittance due to more uniform film deposition. This study underscores the potential of CdO thin films for solar cell applications, as the improvement in transparency and reduced band gap contribute to better light absorption and enhanced electrical conductivity, making them promising for renewable energy technologies.