Can I apply a rain repellent over window tint or film?

On most cars window tint is installed on the inside of the glass, so the outside can be treated as normal glass. If a film is applied to the outside surface, such as some windshield protection films, a glass treatment may not bond to it properly and its solvents may affect the film. In that case, check the film manufacturer's care guidelines before applying anything. Never apply exterior rain repellents to the inside of tinted windows.