John Paul Hempel (October 14, 1935 – January 13, 2022) was an American mathematician specialising in geometric topology.
Hempel was born in Salt Lake City, Utah. In 1957 he graduated from the University of Utah with a degree in mathematics. In 1962, he defended his thesis at the University of Wisconsin-Madison, under the supervision of R. H. Bing. He was a professor at Rice University until the time of his death.
In 2013, Hempel was elected a fellow of the American Mathematical Society.
He also introduced the study of the curve complex into 3-manifold topology.
Hempel wrote a book about 3-manifolds in 1976.
He was married to Edith, whom he married on September 1, 1965, in Houston, Texas; they had one son.