Correctly modelling the intricate structure of QCD scattering amplitudes is crucial for many high-energy physics experiments. This in particular also applies to the treatment of their soft and collinear regions, which are readily probed by experimental measurements, but where the application of fixed-order perturbation theory is doubtful. Event generator software aims to model QCD effects in as much detail as possible. An important component of these tools are parton shower algorithms that encode the evolution of cross sections in the soft- and collinear regions. Due to the complexity of multi-parton phase space, parton showers have, since their inception, been limited to lowest order precision. For a consistent NLO event generator framework, and to reduce the uncertainties inherent in a lowest-order approach, it is important to remove this parton-shower induced obstacle. In this talk, I will discuss recent advances towards a consistent definition and implementation of next-to-leading order parton showers within the Pythia and Sherpa event generators.