Leja is a surname. Notable people with this surname include:
Franciszek Leja (1885–1975), Polish mathematician Frank Leja (1936–1991), U.S. baseball player Łukasz Leja, Polish-born American painter Walter Leja (1921–1992), Polish-born Canadian bomb disposal expert and soldier
See also Lajat (alternatively spelled Leja), largest lava field in Syria