Many-body perturbation theory is applied to compute the quasiparticle electronic structures and the optical absorption spectra (including excitonic effects) for several transparent conducting oxides (TCOs). We discuss HSE+G0W0 results (based on the hybrid exchange-correlation functional by Heyd, Scuseria, and Ernzerhof, and quasiparticle corrections from approximating the electronic self energy as the product of the Green’s function and the screened Coulomb interaction) for band structures, fundamental band gaps, and effective electron masses of magnesium oxide, zinc oxide, cadmium oxide, tin dioxide, tin oxide, indium (III) oxide and silicon dioxide. The Bethe–Salpeter equation (BSE) is solved to account for excitonic effects in the calculation of the frequency-dependent absorption coefficients. We show that the HSE+G0W0 approach and the solution of the BSE are very well suited to describe the electronic structure and the optical properties of various TCOs in good agreement with experiment.