DUNE is an international project, currently in its design phase, for neutrino physics and proton-decay searches. It will consist of two detectors exposed to a megawatt-scale muon neutrino beam that will be produced at Fermilab (Illinois, USA). One detector will record particle interactions near the source of the beam, while a second, much larger, detector comprising four 10-kilotonne liquid argon TPCs will be installed at a depth of 1.5~km at SURF (South Dakota, USA), about 1300 kilometres away of the neutrino source. Among the primary scientific goals of DUNE is the precision measurement of the parameters that govern neutrino mixing, including those still unknown: the octant in which the $\theta_{23}$ mixing angle lies, the neutrino mass ordering and the value of the CP violation phase. This paper discusses the sensitivity of the DUNE experiment to these parameters.