Lowell P. Hager (1926 − 15 April 2014)[1] was an internationally known enzymologist and protein chemist. He was head of the department of biochemistry at the University of Illinois where he was a member of the faculty since 1960 and head of the department for 20 years.[2] He was elected to the National Academy of Sciences in 1995.[3] He was best known for his work on halogenating enzymes and heme peroxidases, chemicals found widely in biochemical systems.[1]