  Lepton universality, meaning the equal coupling of the electroweak gauge
bosons to the different lepton flavours, is a central property of the Standard
Model (SM). Tests of lepton universality in ratios of rates of $b\to
s\ell^+\ell^-$ decays involving electron and muon final states profit from
precise SM predictions, free from hadronic uncertainties. They therefore
constitute particularly powerful probes for New Physics (NP) scenarios. These
proceedings summarise the latest and most precise tests of lepton universality
in rare $b\to s\ell^+\ell^-$ transitions by the LHCb collaboration.
