A multilayer ceramic electronic component may include: a plurality of active parts including a plurality of dielectric layers and a plurality of internal electrodes that are alternately disposed, the plurality of active parts being stacked; an interlayer margin part disposed between the active parts adjacent to each other and containing magnesium; an upper cover part disposed on an upper portion of an uppermost active part among the plurality of active parts and containing magnesium; and a lower cover part disposed on a lower portion of a lowermost active part among the plurality of active parts and containing magnesium, wherein the upper and lower cover parts and the interlayer margin part include magnesium-nickel oxide layers formed on interfaces thereof adjacent to the active parts.