A composite cathode active material includes: a core including a plurality of primary particles; and a shell on the core, wherein the primary particles include a first lithium transition metal oxide comprising nickel, the shell includes a first layer and a second layer on the first layer, the first layer includes a first composition containing a first metal, the second layer includes a second composition containing phosphorus, and the first metal includes at least one or more metal, other than nickel, belonging to any of Groups 2 to 5 and Groups 7 to 15 of the Periodic Table of the Elements. Also a cathode, and a lithium battery each including the composite cathode active material, and a method of preparing the composite cathode active material.