The angular distributions and the differential branching fraction of the decay (B^{0} \to K^{}(893)^{0}\mu^{+}\mu^{-}) are studied using data corresponding to an integrated luminosity of 20.5 fb⁻¹ collected with the CMS detector at the LHC in pp collisions at (\sqrt{s}) = 8 TeV. From 1430 signal decays, the forward-backward asymmetry of the muons, the (K^{}(892)^{0}) longitudinal polarization fraction, and the differential branching fraction are determined as a function of the dimuon invariant mass squared. The measurements are among the most precise to date and are in good agreement with standard model predictions.