In an electron microscope equipped with sextupole correctors the ultimate resolution is limited by the fifth‐order spherical aberration of the optical system used to form the electron probe. We have examined the possibilities of using octupoles in order to correct this fifth‐order spherical aberration. We find that for an electrostatic octupole, the fifth‐order aberration is symmetric, while for a magnetic octupole the fifth‐order aberration is asymmetric but it is possible to reduce this asymmetry by properly arranging the initial conditions. Based on these results, we propose a system which could be used to correct fifth‐order aberration in a probe forming system equipped with a sextupole corrector.