Provided are a cathode active material for a lithium secondary battery, a method of preparing the same, and a lithium secondary battery including a cathode including the cathode active material. The cathode active material includes: a secondary particle of a nickel-based active material, wherein the secondary particle including a plurality of primary particles, wherein the secondary particle includes a radial arrangement structure and an irregular porous structure, the radial arrangement structure is located closer to a surface of the secondary particle than the irregular porous structure, and a lithium fluoride-based compound is present on a surface of the nickel-based active material.