Villarreal Club de Fútbol, S.A.D. (Valencian: Vila-real Club de Futbol, S.A.D.), usually abbreviated to Villarreal CF or simply Villarreal, is a professional football club based in Villarreal, in Castellón in eastern Spain, that plays in La Liga, the top flight of Spanish football.

Founded in 1923, the club spent much of its history in the lower divisions of Spanish football and made their La Liga debut only in 1998. In the 21st century, Villarreal gained some league stability, although they sustained relegation in 2012, rebounding the next year and then remaining in the top division to date. The club made its first appearance in the UEFA Champions League in 2005, with its best result being the semi-finals in 2006 and 2022. Villarreal also appeared in the UEFA Europa League during this time, and won the competition in 2021 by defeating Manchester United in the final, clinching their first major trophy.

The club is nicknamed El Submarí Groguet or El Submarino Amarillo (Yellow Submarine) due to its yellow home kit, and due to being a low-profile team compared to Real Madrid, Barcelona, Atlético Madrid, and regional rivals Valencia. They play their home games at the Estadio de la Cerámica, and have been touted as an example of a small but successful club.

Villarreal CF was founded as Club Deportivo Villarreal on 10 March 1923 "to promote all sports especially Football." The stadium was rented for 60 pesetas a month and ticket prices were set at half a peseta for men and a quarter of a peseta for children. Women were granted free admission. On 17 June 1923, Castellón, a modern rival of the club, played the first match against a club named after Miguel de Cervantes. On 21 October of that year, Villarreal played their first game ever, playing against Castellón. Villarreal started off with a kit of white shirts and black shorts, reflected in their first badge.