  Large classes of non-supersymmetric string models equipped with
standard-model features have been constructed, but very little of their
phenomenology is known. Interestingly, their spectra exhibit scalar fields
whose only couplings to observed particles is through a multi-Higgs sector. On
the other hand, bottom-up models with Higgs portals offer still an acceptable
framework for dark matter. We explore realizations of such Higgs portals in
promising heterotic orbifold models without supersymmetry. We find that a
sample model includes Higgs vacua that are stable at one-loop, in which the
Higgs sector is compatible with particle-physics observations and a scalar can
account for the measured dark matter abundance. In such vacua, interesting
constraints on the masses of the dark matter candidate and the heavy Higgs
sector are uncovered. These compelling results are not limited to string
models, as they can be embedded in similarly motivated bottom-up schemes.
