A positive electrode for a secondary battery includes a positive electrode active material layer, which includes a positive electrode active material including a lithium transition metal oxide which contains nickel, cobalt, and manganese and has an atomic ratio of nickel in total transition metals of 80 atm % or more, and a metal oxide including a metallic element having a binding potential with lithium of 0.5 V to 4 V. A secondary battery including the positive electrode is also provided.