  We investigate the possibility of gauge coupling unification in various
radiative neutrino mass models, which generate neutrino masses at one- and/or
two-loop level. Renormalization group running of gauge couplings is performed
analytically and numerically at one- and two-loop order, respectively. We study
three different classes of neutrino mass models: (I) minimal ultraviolet
completions of the dimension-7 $\Delta L=2$ operators which generate neutrino
masses at one- and/or two-loop level without and with dark matter candidates,
(II) models with dark matter which lead to neutrino masses at one-loop level
and (III) models with particles in the adjoint representation of
$\mathrm{SU}(3)$. In class (I), gauge couplings unify in a few models and
adding dark matter amplifies the chances for unification. In class (II), about
a quarter of the models admit gauge coupling unification. In class (III), none
of the models leads to gauge coupling unification. Regarding the scale of
unification, we find values between $10^{14}$ GeV and $10^{16}$ GeV for models
belonging to class (I) without dark matter, whereas models in class (I) with
dark matter as well as models of class (II) prefer values in the range $5 \cdot
10^{10}-5 \cdot 10^{14}$ GeV.

High Energy Physics - Phenomenology