The measurement of diboson production processes serves as an excellent probe to test the electroweak sector of the Standard Model. Moreover, it allows for studying cross sections in dependence of the vector boson polarization, which is of particular interest due to the direct connection between the longitudinal polarization and the electroweak symmetry breaking mechanism. The increasing luminosity of the Large Hadron Collider necessitates precise theoretical predictions for these processes to compare with. This contribution provides an overview over state-of-the-art and new calculations for both unpolarized and polarized diboson production processes. For polarized cross sections, this includes the presentation of two new Monte Carlo codes that, for the first time, allow for the simulation of fully realistic, polarized events including higher-order QCD effects.