Flier is a surname. Notable people with the surname include:
Henk van der Flier (born 1945), Dutch psychologist
Jaap Flier (born 1934), Dutch ballet dancer and choreographer
Jeffrey Scott Flier (born 1948), American physician, endocrinologist, researcher and Dean of the Faculty of Medicine at Harvard University
Manon Flier (born 1984), Dutch volleyball player
Yakov Flier (1912-1977), Russian concert pianist and teacher