  Observation of lepton number ($L$) violation by two units at colliders would
provide evidence for the Majorana nature of neutrinos. We study signals of
$L$-violation in the context of two popular models of neutrino masses, the
type-II seesaw model and the Zee model, wherein small neutrino masses arise at
the tree-level and one-loop level, respectively. We focus on $L$-violation
signals at the LHC arising through the process $pp \to \ell^{\pm}\ell^{\prime
\pm}$ + jets within these frameworks. We obtain sensitivity to $L$-violation in
the type-II seesaw model for triplet scalar masses up to 700 GeV and in the Zee
model for charged scalar masses up to 4.8 TeV at the high-luminosity LHC with
an integrated luminosity of $3~\text{ab}^{-1}$.
