New spectroscopic observations have been obtained for a sample of H II regions located toward the galactic anticentre region. The sample includes H II regions with known galactocentric distances, having their ionising stars clearly identified from previous work. The spectra correspond to low- to intermediate-excitation nebulae, ionised by one (few) late O-early B star(s). The global parameters of the H II regions as well as their physical parameters have been derived. Abundances have been computed using direct determinations of the electron temperature for some of the objects or alternatively, by adopting an electron temperature from radio data or model fitting. Overall, the data appear to show a nearly flat gradient of oxygen and nitrogen abundances up to 18 kpc of galactocentric distance.