Giovanni Costigan (1905–1990) was a noted historian and specialist in Irish and English history. Costigan was educated at the University of Oxford. He received a Master of Arts at the University of Wisconsin–Madison where he earned his PhD. In 1934 he joined the history department at the University of Washington where he served for 41 years. He was a staunch critic of American involvement in the Vietnam war.
- The Legendary Giovanni Costigan: Specialist in English and Irish History a tribute from the University of Washington
- Giovanni Costigan, 85, A Professor of History New York Times obituary