The implementation of cost-effective fuel cells and metal-air batteries requires developing an environmentally friendly, cost-effective, and high performance electrocatalyst for the oxygen reduction reaction (ORR). While several oxides have been proposed as electrocatalysts for the ORR in basic conditions, some sulfides, particularly copper sulfide, have been shown to provide some of the highest electrical conductivities and overall improved electrocatalytic properties. We use here first-principles calculations to study the oxygen adsorption and ORR kinetics on alternative copper-based sulfides and find out that the inclusion of cations with a higher oxidation state, such as Zn2+ and Sn4+, provides more energetically favorable sites for oxygen adsorption and subsequent formation of hydroxyls. DFT calculations show all species in the OOH* dissociation pathway to preferentially adsorb on Sn4+ and Zn2+ sites, providing low energy barriers of the rate-determining step. Supported by these calculations, we synthesized Cu2ZnSnS4 (CZTS) nanocrystals (NCs) with a controlled crystallographic phase by high-yield colloidal synthesis routes and investigated their electrocatalytic properties toward ORR in alkaline solution. Kesterite CZTS NCs show exceptional electrocatalytic performance for ORR with high current densities (5.45 mA cm(-2) at 0.1 V vs RHE) and low onset reduction potential (0.89 V vs RHE), comparable to commercial Pt/C electrocatalysts. Equally important, CZTS NCs exhibit superior stability and resistance to methanol, thus avoiding the poisoning limitation of commercial Pt/C catalysts in the particular case of direct methanol fuel cells.