  We construct intersecting D5-brane orbifold models that yield the
(non-supersymmetric) standard model up to vector-like matter and
charged-singlet scalars.
  The models are constrained by the requirement that twisted tadpoles cancel,
and that the gauge boson coupled to the weak hypercharge $U(1)_Y$ does not get
a string-scale mass via a generalised Green-Schwarz mechanism. Gauge coupling
constant ratios close to those measured are easily obtained for reasonable
values of the parameters, consistently with having the string scale close to
the electroweak scale, as required to avoid the hierarchy problem.
