Ihara (written: 井原 or 伊原) is a Japanese surname. Notable people with the surname include:
Haruki Ihara (伊原 春樹) (born 1949), Japanese baseball player and managerIsamu Ihara (井原 勇) (1926–2007), Japanese politicianKeiko Ihara (井原 慶子) (born 1973), Japanese racing driverMasami Ihara (井原 正巳) (born 1967), Japanese footballerMichio Ihara (born 1928), Japanese sculptorIhara Saikaku (井原 西鶴) (1642–1693), Japanese poet and writerTsuyoshi Ihara (伊原 剛志) (born 1963), Japanese actorYasuhide Ihara (井原 康秀) (born 1973), Japanese footballerYasutaka Ihara (伊原 康隆) (born 1938), Japanese mathematician