The study of vector-boson pair production in association with jets is one of the key signatures for the analysis of the electroweak symmetry breaking mechanism. While the vector bosons are the clear signs of electroweak dynamics, the associated jets are important tags to suppress backgrounds and probe the kinematic dependence of the interactions. At high jet multiplicity the di-vector boson signature plays a particularly important role as background to Higgs transverse momentum distribution, vector boson scattering, top-quark physics as well as background for searches of new physics. Given the rather small cross section, this process class will rise to particular importance in the ongoing physics run at the LHC with more data and center-of-mass energy available. In this talk we present for the first time Next-to-Leading Order QCD corrections to the Standard Model production of oppositely charged W-bosons in association with up to three jets. The results are obtained by using modern on-shell and unitarity methods, which have been implemented in the BlackHat program. We present predictions for total and differential cross sections at the LHC following previous related studies by ATLAS and CMS. The quantum corrections reduce considerably spurious renormalisation and factorisation scale dependence of the predictions. Finally, we discuss universal features that appear at large jet multiplicities.