The present invention relates to a lithium secondary battery which includes a positive electrode including an overlithiated manganese-based oxide, in which an amount of manganese among total metals excluding lithium is greater than 50 mol % and a ratio (Li/Me) of the number of moles of the lithium to the number of moles of the total metals excluding the lithium is greater than 1, as a positive electrode active material; a negative electrode including a silicon-based negative electrode active material; a separator disposed between the positive electrode and the negative electrode; and an electrolyte, and satisfies Equation (1). 0.25 A ≤ B ≤ 0 . 6 ⁢ A Equation ⁢ ( 1 ) In Equation (1), A is a discharge curve area in a voltage range of 2.0 V to 4.6 V of a dQ/dV graph obtained by differentiating a graph of battery discharge capacity Q and voltage V after one cycle which are measured while charging the lithium secondary battery at 0.1 C to 4.6 V and then discharging the lithium secondary battery at 0.1 C to 2.0 V, and B is a discharge curve area in a voltage range of 2.0 V to 3.5 V of the dQ/dV graph.