Measurements are presented of electroweak boson production using data from pp collisions at a centre-of-mass energy of s√=8s=8 TeV. The analysis is based on an integrated luminosity of 2.0 fb−1 recorded with the LHCb detector. The bosons are identified in the W → μν and Z → μ + μ − decay channels. The cross-sections are measured for muons in the pseudorapidity range 2.0 < η < 4.5, with transverse momenta p T > 20 GeV/c and, in the case of the Z boson, a dimuon mass within 60