This Report documents the results obtained by the Working Group on Quantum
ChromoDynamics and the Standard Model for the Workshop ``Physics at TeV
Colliders'', Les Houches, France, 21 May - 1 June 2001. The
account of uncertainties in Parton Distribution Functions is
reviewed. Progresses in the description of multiparton final states at
Next-to-Leading Order and the extension of calculations for precision QCD
observables
beyond this order are summarized. Various issues concerning the
relevance of resummation for observables at TeV colliders is
examined. Improvements to algorithms of jet reconstruction are discussed
and predictions for
diphoton and photon pi-zero production at the LHC are made for
kinematic variables of interest regarding searches for a Higgs boson
decaying into two photons. Finally, several improvements implemented in
Monte-Carlo
event generators are documented.