A negative active material including: a porous silicon-carbon secondary particle including: a plurality of silicon-carbon primary particles including a plurality of silicon-carbon primary particles including a silicon material, and a first carbonaceous material, wherein an apparent density of a silicon-carbon primary particle of the plurality of silicon-carbon primary particles is about 2 grams per cubic centimeter or greater; and a second carbonaceous material, wherein the second carbonaceous material is disposed on the plurality of silicon-carbon primary particles.