Cecilia is a census-designated place (CDP) in St. Martin Parish, Louisiana, United States. The population was 1,505 at the 2000 census. It is part of the Lafayette Metropolitan Statistical Area.
Cecilia is located at 30°20′11″N 91°50′52″W / 30.33639°N 91.84778°W / 30.33639; -91.84778 (30.336379, -91.847867).
According to the United States Census Bureau, the CDP has a total area of 1.7 square miles (4.5 km²), all of it land.