  Gamma-ray binaries (GBs) have been object of intense studies in the last
decade. From an observational perspective, GBs are phenomenologically similar
to most X-ray binary systems in terms of their broad-band emission across the
entire electromagnetic spectrum, being segregated from this source population
by showing a maximum of their spectral energy distribution in the gamma-ray
band, either at high-energies (HE: 100 MeV - 100 GeV) or very-high energies
(VHE: above 100 GeV). From a theoretical perspective, the broad-band emission
from GBs is a unique case in which particle acceleration and
emission/absorption mechanisms can be tested against periodically changing
conditions of their immediate surroundings. In this proceedings we examine some
of the key observational results of the multi-wavelength emission from GBs. We
discuss the correlated/contemporaneous emission observed in several of these
systems, from radio to gamma-rays, by considering a single underlying
particle-emitting population and the properties of the nearby photon, matter
and magnetic ambient fields.
