This application relates to a cathode active material for a lithium secondary battery, a method of preparing the cathode active material, a cathode employing the cathode active material, and a lithium secondary battery employing the cathode. The cathode active material may include a secondary particle in which primary particles are aggregated and a first coating layer disposed on the plurality of primary particles to have a thickness of about 2.5 nm or less and including a NiO-like crystalline phase belonging to a Fm3-m space group. The cathode active material may prevent surface deterioration through a washing process using a weakly acidic or neutral organic buffer, thereby improving the initial efficiency characteristic and life characteristics of the lithium secondary battery while maintaining the initial capacity of the lithium secondary battery.