  Higgs pair production is not only sensitive to the trilinear Higgs
self-coupling, but it can give access to other anomolous couplings, as e.g. a
novel $hht\bar{t}$ coupling. In Composite Higgs Models, this coupling usually
leads to a large increase of the cross section. In such a framework an
interesting question is, whether it might be possible to observe new physics
for the first time in Higgs pair production. This question will be addressed by
taking into account projected sensitivities for Higgs coupling measurements and
for direct searches of new vector-like quarks. Higher order corrections to
Higgs pair production via gluon fusion are sizeable. It is hence not only
important to compute them in the Standard Model (SM) but also in its
extensions. Here, the computation of the QCD corrections in the SM with
dimension 6 operators as well as the SUSY-QCD corrections to Higgs pair
production via gluon fusion in the MSSM are presented.
