  In a number of Higgs-portal models, an $SU(2)$ isospin-singlet scalar boson
generically appears at the electroweak scale and can mix with the Standard
Model (SM) Higgs boson with a mixing angle $\alpha$. This singlet scalar boson
can have renormalizable couplings to a pair of dark matter particles,
vectorlike leptons or quarks, or new gauge bosons, thereby modifying the Higgs
signal strengths in a nontrivial way. In this work, we perform global fits to
such models using the most updated LHC Higgs-boson data and discuss the
corresponding implications on Higgs-portal-type models. In particular we find
that the current LHC Higgs-boson data slightly favors the SM over the
Higgs-portal singlet-scalar models, which has to be further examined using the
upcoming LHC Higgs-boson data. Finally the Higgs-portal models are constrained
as follows: $\cos\alpha \gtrsim 0.86$ and $\Delta \Gamma_{\rm tot} \lesssim
1.9$ MeV at 95 \% CL.
