A positive electrode active material for a secondary battery is provided. The positive electrode active material is a secondary particle including primary particles of a lithium composite metal oxide that contains nickel, cobalt, and manganese, wherein the manganese content in the lithium composite metal oxide exceeds 50 at % with respect to the sum content of nickel, cobalt, and manganese, and the primary particle is doped with one or two or more dopant elements selected from the group consisting of Nb, Sn, Mo, and Ta, the dopant element content being higher in a surface region of the primary particle than in the interior of the primary particle, and the dopant element concentration being 500 to 5,000 ppm with respect to the total weight of the positive electrode active material. In addition, a lithium secondary battery which includes the positive electrode active material is provided.