Measurements by the ATLAS and CMS Collaborations, sensitive to various aspects of the modelling of QCD, are presented. This includes the production of jets, inclusively and in association with $Z$ bosons, as well as the production of photon pairs and the fragmentation of heavy quarks into hadrons. The measurements are compared to fixed-order perturbative predictions where available, as well as to Monte Carlo simulations including different algorithms for the matrix element calculation, the parton shower emissions and the hadronisation model. Determinations of the parton distribution functions inside the proton are also presented by both Collaborations.