  Gamma-ray binaries are suitable sources to study high-energy processes in
jets and outflows in general. In the last years, there has been a lot of
activity in the field of gamma-ray binaries to identify the different factors
that shape their non-thermal spectra, which ranges from radio to very high
energies, as well as their lightcurves. In this work, I discuss the main
aspects of the non-thermal emission in this class of objects, which presently
includes high-mass microquasars, high-mass binaries hosting a non-accreting
pulsar and, probably, massive star binaries; few potential candidates to be
gamma-ray binaries are also presented. Finally, the importance of gamma-ray
absorption is discussed, and the main physical ingredients, which are likely
involved in the non-thermal radiation in gamma-ray binaries, are briefly
considered.
