  We evaluate the amplitude for gamma gamma --> pi^+ pi^- to two loops in the
framework of chiral perturbation theory.The three new coupling constants that
enter the result at this order in the low-energy expansion are estimated via
resonance saturation. We discuss in addition the crossed channel processes
gamma pi^+ --> gamma pi^+ - in particular the charged pion polarizabilities -
to the same accuracy. The predictions are compared with available experimental
information.
