Precision tests of the Standard Model with hadronic tau decays

Several experimental commlatorations have invested considerable effort in making precise measurements of hadronic tau decays. New measurements are expected from the Tau-Charm and B [Super-B, Belle-II] factories. We will review precision tests of the Standard Model implied by such measurements. By making an accurate determination of the strong coupling constant alpha_s, hadronic tau decays provide an excellent laboratory to test precisely Quantum Chromodynamics. Equally important, hadronic tau decays can be used to probe the electroweak interaction; in this respect, we will discuss extraction of the CKM matrix element |V_{us}|.