To provide an industrially advantageous oxidative desulfurization of fuel oil which can efficiently oxidize and remove hardly removable organic sulfur compounds contained in fuel oil, particularly benzothiophenes.

The oxidative desulfurization of fuel oil comprises treating a sulfur compound-containing fuel oil with an oxidizing agent in the presence of a promoter selected from (i) a transition metal catalyst, (ii) a phase transfer catalyst and (iii) a Bronsted acid.