Cross-section data, both for elastic and inelastic electron collisions with molecular oxygen, in the energy range 0.1-10 keV, have been obtained in this study by combining theoretical and experimental methods. Accurate total cross-sections (within 3%) have been measured in a transmission beam system for electron energies ranging from 400 to 5500 eV. Differential and integral elastic cross-sections have been calculated by means of a scattering potential method in the framework of the independent atom model at electron energies ranging from 0.1 to 10 keV. The consistency of our theoretical and experimental results has been confirmed by comparison with previous elastic and ionisation experimental cross-sections.