A hardmask composition includes a first material including one of an aromatic ring-containing monomer and a polymer containing a repeating unit including an aromatic ring-containing monomer, a second material including at least one of a hexagonal boron nitride and a precursor thereof, a chalcogenide-based material and a precursor thereof, and a two-dimensional carbon nanostructure and a precursor thereof, the two-dimensional carbon nanostructure containing about 0.01 atom % to about 40 atom % of oxygen, and a solvent.