The cathode active material according to exemplary embodiments includes lithium metal oxide particle including a layered crystal structure and a cubic crystal structure, wherein the lithium metal oxide particle contains 80 mol % or more of nickel based on a total number of moles of all elements except for lithium and oxygen, and the lithium metal oxide particle includes the cubic crystal structure only in a region having a thickness of less than 200 nm from a surface thereof when analyzing a crystal structure thereof by a high-resolution transmission electron microscopy.