Zinc oxide (ZnO) was deposited by sputtering on silicon substrates. The structure and the composition of these deposits were studied by X-ray diffraction and Rutherford backscattering spectrometry, respectively. It was found that the thin films are polycrystalline with an hexagonal wurtzite structure and have a crystallographic c-axis orientation perpendicular to the substrate surface. When the thickness of the coatings increases from 50 to 600 nm, the grain size and the density increase whereas the O/Zn atomic ratio decreases. Then ZnO coatings were deposited on bisphenol-A polycarbonate (PC) films in order to protect this polymer against the solar ultraviolet (UV) radiations. Samples were irradiated in artificial accelerated conditions with a polychromatic light (lambda>300 nm). The rate of photodegradation was evaluated by infrared and UV–visible spectroscopies. ZnO coatings decrease the rate of oxidation and the rate of photo-yellowing of PC. The efficiency of the ceramic coating depends on its thickness and its structural properties. As a conclusion, ZnO coatings can improve the long-term behaviour of PC for outdoor applications.