  The Higgs boson with a mass $M_H \approx 126$ GeV has been observed by the
ATLAS and CMS experiments at the LHC and a total significance of about five
standard deviations has been reported by both collaborations when the channels
$H\to \gamma \gamma$ and $H\to ZZ \to 4\ell$ are combined. Nevertheless, while
the rates in the later search channel appear to be in accord with those
predicted in the Standard Model, there seems to be an excess of data in the
case of the $H\to \gamma\gamma$ discovery channel. Before invoking new physics
contributions to explain this excess in the di--photon Higgs rate, one should
verify that standard QCD effects cannot account for it. We describe how the
theoretical uncertainties in the Higgs boson cross section for the main
production process at the LHC, $gg \to H$, which are known to be large, should
be incorporated in practice. We further show that the discrepancy between the
theoretical prediction and the measured value of the $gg \to H \to \gamma
\gamma$ rate, reduces to about one standard deviation when the QCD
uncertainties are taken into account.
