Light traveling path management is one of the key technologies to improve the performance of lighting, displays, and solar cells. Here we report broadband ultra-wide-angle optical diffusers using ZnO nanowires grown on flexible substrates by aqueous chemical bath deposition. The growth behavior of ZnO nanostructures strongly influences the degree of light scattering and is mainly governed by the molecular complexes present in the chemical bath, their relative concentration, and their interactions, which were efficiently controlled by the ammonia concentration in this work. Our ZnO nanowires grown at optimal ammonia concentrations exhibit higher optical transmission haze values than previously reported ZnO nanostructures over broadband (400 – 800 nm). In addition, our ZnO nanowires exhibit larger values in the key parameters of total transmittance and light scattering angle than commercial 3 M™ optical diffusers 3635–30/3635–70. Therefore, our chemical bath deposited ZnO nanowires are expected to be a compelling solution for optical diffusers in display and lighting applications.