One of the most famous sites in the history of Theater, Sikyon (or Sicyon) boasts a well preserved Greek theater whose excavation illuminates the structures which supported Greek drama from the 5th century B.C. into the Roman period. This report represents the first systematic excavation of this key site and forms the basis for subsequent scholarship on both the technical and literary aspects of Greek theater. The site report includes inscriptions from the theater and surrounding area, artifacts found within the site, plans of the super- and sub-structures of the theater, and photographs of the site under excavation. This often cited report is still a key document to historians of theater, classicists, and archaeologists.