Provided are an acoustic diaphragm and an acoustic device including the same. The acoustic diaphragm may include graphene nanoparticles, and an average particle size of the graphene nanoparticles may be about 10 nm or less. The graphene nanoparticles substantially may have a particle size of about 1 nm to about 10 nm. The graphene nanoparticles may include at least one functional group selected from a hydroxyl group, a carboxyl group, a carbonyl group, an epoxy group, an amine group, and an amide group.