Guy I of Thouars

Guy I of Thouars (1183–1242) was a Poitevin nobleman of the house of Thouars, the second son of Viscount Aimery VII. He became lord of Vihiers in 1227 and in 1234 succeeded his uncle Raymond I as the twenty-first viscount of Thouars.

In the struggles between the English and French crowns in western France, Guy stayed loyal to Henry III of England, whom he supported in Poitou. He died at the beginning of April 1242, as Hugh X of Lusignan, count of La Marche, rose in revolt against Capetian rule, and was succeeded by his brother Aimery VIII.