Legrain is a French surname. Notable people with the surname include:
Georges Legrain (1865–1917), French Egyptologist Marcel Legrain (1890–1915), French rugby union player Paul Legrain, French cyclist Philippe Legrain, British political economist and writer Pierre Legrain (1920–2005), French hammer thrower Sarah Legrain (born 1985), French politician
See also (born 1988), French beauty pageant winner