The ratio ..lambda../sub MO//..lambda../sub latt/ is computed for quantum chromodynamics (QCD) with massless fermions present. The result obtained, using the Wilson form of the lattice action, is ..lambda../sub MO//..lambda../sub latt/ = 117.5. We show how our methods can readily be extended to other forms of the action. Appendices give details of the technology of QCD perturbation theory on the lattice. Included are derivations of Feynman rules and Ward identities as well as general power-counting arguments and a discussion of the renormalization group.