In one embodiment, the present disclosure relates to a method of preparing a positive electrode active material, which includes mixing a nickel cobalt manganese hydroxide precursor containing nickel in an amount of 60 mol % or more based on a total number of moles of transition metals in the precursor, a lithium-containing raw material, and a doping raw material represented by Formula 2 (set forth herein), and sintering the mixture to prepare a positive electrode active material represented by Formula 1 (set forth herein).