A positive electrode material and a positive electrode and a lithium secondary battery including the same are provided. The positive electrode material having a bimodal particle size distribution which includes large-diameter particles and small-diameter particles having different average particle diameters (D50), wherein the large-diameter particles are lithium composite transition metal oxide having a nickel content of 80 atm % or more in all transition metals thereof, and the small-diameter particles are a lithium composite transition metal oxide including nickel, cobalt, and aluminum, having a nickel content of 80 atm % to 85 atm % in all transition metals, and having an atomic ratio of the cobalt to the aluminum (Co/Al) of 1.5 to 5.