Cecilia is a census-designated place (CDP) in St. Martin Parish, in the U.S. state of Louisiana. The community lies within the region of Acadiana, and the Lafayette metropolitan statistical area. It had a population of 1,505 at the 2000 U.S. census, estimated to have grown to 1,917 in 2019 at the American Community Survey's 5-year estimates.

St. Martin Parish is a parish located in the U.S. state of Louisiana, founded in 1811. Its parish seat is St. Martinville, and the largest city is Breaux Bridge. At the 2020 census, the population was 51,767. St. Martin Parish is part of the Lafayette metropolitan area in the region of Acadiana, along the Gulf Coast.