The oxygen reduction reaction (ORR) is a key reaction for fuel cells and metal–air batteries. In this work, zinc sulfide (ZnS) nanoparticles were supported by reduced graphene oxide (rGO) and utilized for the ORR. Scanning electron microscopy and transmission electron microscopy profiles reveal that the ZnS nanoparticles are uniformly distributed on the rGO. Cyclic voltammograms, rotating disk electrode and rotating ring disk electrode measurements demonstrated that the hierarchical ZnS/rGO sheets exhibited excellent electrocatalytic activity for the ORR in an alkaline medium, which was evidenced by their high cathodic current density, positive onset potential, low H₂O₂ yield, and high electron transfer number. Chronoamperometric studies revealed the excellent catalytic stability of the prepared catalyst. The catalytic activity and stability in the alkaline electrolyte indicated that ZnS/rGO sheets have great potential as alternatives to precious metal-based catalysts.