  We study the two-Higgs-doublet model with type-II seesaw mechanism. In view
of constraints from the Higgs data, we consider the aligned two-Higgs-doublet
scheme and its effects on muon anomalous magnetic dipole moment, $a_{\mu}$,
including both one-loop and two-loop Barr-Zee type diagrams. Thanks to a
sizable trilinear scalar coupling, the Barr-Zee type diagrams mediated by the
Higgs triplet fields have a dominant effect on $a_{\mu}$. In particular, unlike
the usual two-Higgs-doublet models that require exotic Higgs bosons light in
mass, the masses of the corresponding particles in the model are of ${\cal
O}(100)$~GeV. The doubly-charged Higgs boson presents a different decay pattern
from the usual Higgs triplet model and thus calls for a new collider search
strategy, such as multi-$\tau$ searches at the LHC.
