MoS₂ nanodots (NDs) were successfully embedded in the three-dimensional (3D) porous frameworks of N-doped graphene (NGr) via in situ pyrolysis of glucose, a layered C₃N₄ sacrificial template and monolayered MoS₂ NDs. The monolayered MoS₂ NDs were hydrothermally pre-synthesized and acted as size-controlled precursors. By varying the content of the MoS₂ NDs, a series of MoS₂ NDs/NGr was obtained, which displayed amendable activity towards oxygen reduction reaction (ORR) in basic solution, due to the balance between the exposed edge sites of the MoS₂ NDs and the internal conductive channels of the 3D porous NGr. The optimal composition generated an efficient Pt-free ORR catalyst with good four-electron selectivity, and was shown to have a more positive shift in both the onset and peak potentials than its counterparts. The novel catalyst also demonstrated superior tolerance against methanol and better durability than commercial Pt/C.