Gagnoa is a city in south-central Ivory Coast. It is the seat of both Gôh-Djiboua District and Gôh Region. It is also the seat of and a sub-prefecture of Gagnoa Department. Gagnoa is also a commune. In the 2014 census, its population was 213,918, making it the seventh-largest city in the country.
Gagnoa is the seat of the Roman Catholic Archdiocese of Gagnoa, and contains its cathedral.