Recently, there has been much theoretical and experimental focus on dark matter with a mass in the MeV-GeV range.We propose a scenario which not only accommodates this mass scale, but which naturally leads to such a light dark matter candidate. We consider a scenario in which 1st/2nd generation right-handed fermions are charged under a new gauge group, U(1)T3R, which is spontaneously broken to a Z2 subgroup. In this scenario, a Majorana fermion which is odd under the surviving parity is a dark matter candidate. Moreover, the mass of the dark matter particle is tied to the mass of the Standard Model fermions charged under the new U(1), leading to a natural sub-GeV dark matter candidate. This scenario is tightly constrained by direct detection, collider, astrophysical and cosmological data, but there is open parameter space. We comment on the prospects for future experiments to probe this remaining parameter space, and on new cosmological constraints on dark photons coupled to U(1)T3R.
