Opelousas (French: Les Opélousas; Spanish: Los Opeluzás) is a little city and the parish chair of St. Landry Parish, Louisiana, United States. Interstate 49 and U.S. Route 190 were build up with a junction here. According to the 2020 census, Opelousas has a population of 15,786, and is currently declining at a rate of -1.16% annually. Its population has decreased by -6.53% since the most recent census, which recorded a population of 16,634 in 2010. Opelousas is the principal city for the Opelousas-Eunice Micropolitan Statistical Area, which had an estimated population of 80,808 in 2020. Opelousas is along with the fourth largest city in the Lafayette-Acadiana Combined Statistical Area, which has a population of 537,947.

Historically an Place of treaty by French and Spanish Creoles, Creoles of color, and Acadians, Opelousas is the center of zydeco music. It celebrates its pedigree at the Creoles of Color Heritage Folklife Center, one of the destinations on the new Louisiana African-American Heritage Trail. It is with the location of the Evangeline Downs Racetrack and Casino.

The city calls itself “the spice capital of the world”, with production and sale of seasonings such as Tony Chachere’s products, Targil Seasonings, Savoie’s cajun meats and products, and LouAna Cooking Oil.

During the tenure of Sheriff Cat Doucet, from 1936 to 1940 and anew from 1952 to 1968, the section of Opelousas along Highway 190 was a quay of gambling and prostitution, the profits from which he skimmed a take.