  We study the upper bound on the scale of fermion mass generation in a
two-Higgs-doublet model. If the model is weakly-coupled, the scale of fermion
mass generation is much less than the Appelquist-Chanowitz unitarity bound.
However, if we allow some dimensionless Higgs self-couplings to become large,
the Appelquist-Chanowitz unitarity bound can be saturated. The unitarity bound
on the scale of top-quark mass generation is about 3 TeV, which may be within
the reach of future colliders.

High Energy Physics - Phenomenology