| Office: | Senator for Loire-Atlantique |
| Term Start: | 1 October 2011 |
| Office1: | Mayor of Saint-Sébastien-sur-Loire |
| Term Start1: | 19 June 1995 |
| Term End1: | 9 October 2017 |
| Predecessor1: | Martine Laurent |
| Successor1: | Laurent Turquois |
| Birth Date: | df=yes 9 November 1957 |
| Birth Place: | Uckange, France |
| Party: | Horizons (2022–present) |
| Otherparty: | Union of Democrats and Independents Radical Movement |
| Alma Mater: | Panthéon-Sorbonne University |
Joël Guerriau (born 9 November 1957)[1] is a French banker and centre-right politician.[2] A senator for Loire-Atlantique,[3] Guerriau is a secretary of the French Senate and vice-chair of the Committee on Foreign Affairs, Defence and the Armed Forces. He was first elected to the Senate in 2011, then reelected in 2017 and 2023. He sits with The Independents – Republic and Territories group (LIRT).
From 1995 to 2017, he held the mayorship of Saint-Sébastien-sur-Loire. From 1996 to 2011, he also held a seat in the General Council of Loire-Atlantique for the canton of Nantes-10. Guerriau is a knight of the Legion of Honour and officer of the Ordre des Palmes académiques.
Guerriau was taken into custody in November 2023 on suspicion of having drugged Sandrine Josso, a member of the National Assembly,[4] for the purpose of sexual assault.[5] Guerriau is not protected by parliamentary immunity due to an exception for crimes caught in the act.