  Despite much recent progress in model building with D-branes, it has been
problematic to find a completely convincing explanation of gauge coupling
unification. We extend the class of models by considering F-theory
compactifications, which may incorporate unification more naturally. We explain
how to derive the charged chiral spectrum and Yukawa couplings in N=1
compactifications of F-theory with G-flux. In a class of models which admit
perturbative heterotic duals, we show that the F-theory and heterotic
computations match.
