Although carbon-supported platinum (Pt/C) is still considered the most active electrocatalyst for hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), its applications in metal-air batteries as a cathode catalyst, or for oxygen generation via water splitting electrolysis as an anode catalyst is mainly constrained by the insufficient kinetic activity and stability in the oxygen evolution reaction (OER). Here, MOF-253-derived nitrogen-doped carbon (N/C)-confined Pt single nanocrystals (Pt@N/C) have been synthesized and shown to be efficient catalysts for the OER. Even with low Pt mass loading of 6.1 wt% (Pt@N/C-10), the catalyst exhibits greatly improved activity and long-time stability as an efficient OER catalyst. Such high catalytic performance is attributed to the core-shell structure relationship, in which the active N-doped-C shell not only provides a protective shield to avoid rapid Pt nanocrystal oxidation at high potentials and inhibits the Pt migration and agglomeration, but also improves the conductivity and charge transfer kinetics. By using MOF-253 as a carbon template, a well-dispersed and highly stabilized Pt single nanocrystal confined in a N-doped carbon framework is synthesized, and is shown to exhibit a superior OER activity and stability over IrO 2 catalysts.