If dark matter has interactions beyond gravity, we hope to
learn about its nature at collider experiments. Weak interactions with
the Higgs boson, the Higgs portal, suggest the presence of mediator
particles within the energy reach of the LHC. Direct searches for such
mediators are a promising road to probe the Higgs portal, complementary
to dark matter searches in direct detection experiments. We will discuss
the search strategies at the LHC and future colliders in a minimal
renormalizable model where dark matter is a fermion.