  We summarise the prospects for Higgs boson physics at future proton-proton
colliders with centre of mass (c.m.) energies up to 100 TeV. We first provide
the production cross sections for the Higgs boson of the Standard Model from 13
TeV to 100 TeV, in the main production mechanisms and in subleading but
important ones such as double Higgs production, triple production and
associated production with two gauge bosons or with a single top quark. We then
discuss the production of Higgs particles in beyond the Standard Model
scenarios, starting with the one in the continuum of a pair of scalar,
fermionic and vector dark matter particles in Higgs-portal models in various
channels with virtual Higgs exchange. The cross sections for the production of
the heavier CP-even and CP-odd neutral Higgs states and the charged Higgs
states in two-Higgs doublet models, with a specific study of the case of the
Minimal Supersymmetric Standard Model, are then given. The sensitivity of a 100
TeV proton machine to probe the new Higgs states is discussed and compared to
that of the LHC with a c.m. energy of 14 TeV and at high luminosity.
