UV radiation is now of key importance in many fields such as medicine, agriculture, and the integrated circuit manufacturing industry. This use is felt not only in manufacturing processes, but also in the everyday life of every person who has at least once been to the dentist or consumed food pasteurized by the non-thermal method. For this reason, it is very important to control their usage time, as UV rays have both positive and negative effects. In the context of the increasing demand for UV sensors with superior performance, this work investigates the response of Ag2S/ZnO nanostructures to a specific wavelength of 370 nm, revealing a signal almost five times more intense than that obtained at other wavelengths in the ultraviolet spectrum (280–430 nm). For the preparation of these nanostructures, an economical method was used, followed by heat treatment, ensuring the formation of uniform Ag2S nanoparticles arranged on the surface of ZnO columnar crystals. Morphological and compositional characterization was performed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX), revealing a homogeneous distribution of elements and a porous structure that enhances the surface-to-volume ratio. The response and recovery times of the sensor were also measured and values in the order of 1 s were obtained, recommending these nanostructures for applications in rapid detection and real-time monitoring of UV radiation intensity.