  We study the potential of future lepton colliders, running at the Z-pole and
above, and the High-Luminosity LHC to search for the relaxion and other light
scalars $\phi$. We investigate the interplay of direct searches and precision
observables for both CP-even and -odd couplings. In particular, precision
measurements of exotic Z-decays, Higgs couplings, the exotic Higgs decay into a
relaxion pair and associated $Z\phi$ and $\gamma \phi$ production are promising
channels to yield strong bounds.
