Costas M. Soukoulis (Greek: Κώστας Μ. Σούκουλης; 15 January 1951 – 14 March 2024) was a Greek physicist, who was a senior scientist in the Ames Laboratory and a Distinguished Professor of Physics Emeritus at Iowa State University.

He spent three years (1981–1984) at Exxon Research and Engineering Co. and from 1984 was at Iowa State University (ISU) and Ames Laboratory.

Many experimental groups all over the world still use his woodpile structure to fabricate photonic crystals at optical wavelengths, enhance the spontaneous emission and produce nanolasers with low threshold limit.

Soukoulis and Wegener demonstrate magnetic responses[5] and negative index of refraction at optical frequencies [6] in metamaterials, which do not exist in natural materials.

His other researches includes light and Anderson localization, random lasers, graphene and plasmonics.