Disclosed are a cathode active material for a lithium secondary battery and a lithium secondary battery including the same. The cathode active material includes a secondary particle in which a plurality of primary particles are agglomerated, wherein the secondary particle has a predetermined arrangement structure in which (003) surface of primary particles are aligned to be in a vertical direction with respect to a tangent line at a point (P) at which the (003) surface of the primary particles meet a surface of the secondary particle.