Garreau is a French surname. Notable people with the surname include:
Georges Garreau (1902–1986), French diver at the 1924 Olympics Joel Garreau (born 1948), American journalist and writer Lazare Garreau (1812 – 1892), French plant physiologist Ludovic Garreau (born 1983), French ice hockey coach and former player
See also Éliane Jeannin-Garreau (1911–1999), French Resistance member