Guillou is a surname of French origin. It may refer to any the following people:
- Charles Guillou (1813 – 1899), American naval surgeon
- Fernand Guillou (1926 – 2009), French basketball player
- Jan Guillou (born 1944), Swedish writer and journalist
- Jean Guillou (born 1930), French composer, organist, pianist, and pedagogue
- Jean-Marc Guillou (born 1945), French footballer and football manager
- Patrick Guillou (born 1970), French football defender