The LHC and future high-energy colliders offer a unique sensitivity to dark photons (ZD), the mediators of a broken dark U(1) gauge theory that kinetically mixes with the Standard Model hypercharge. In this seminar, we discuss the possible interplay between direct searches of the dark photon arising from Drell-Yan production, and measurements of Higgs exotic decays to dark photons. We also compare the ZD sensitivity at proton-proton colliders to the indirect, but model-independent, sensitivity of global fits to electroweak precision observables as measured at LEP, and at a future ILC/GigaZ machine