Paul Karrer (21 April 1889 – 18 June 1971) was a Swiss organic chemist best known for his research on vitamins.

In 1892 Karrer's family returned to Switzerland where he was educated at Wildegg and at the Old Cantonal School Aarau where he matriculated in 1908.

He studied chemistry at the University of Zurich under Alfred Werner and after gaining his Ph.D. in 1911, he spent a further year as an assistant in the Chemical Institute.

George Wald worked briefly in Karrer's lab while studying the role of vitamin A in the retina.

[2] The Paul Karrer Lecture Foundation is based at the Chemistry Institute of the University of Zurich at Rämistrasse 71, in Zürich.