John Colin Stillwell (born 1942) is an Australian mathematician on the faculties of the University of San Francisco and Monash University.
He was born in Melbourne, Australia and lived there until he went to the Massachusetts Institute of Technology for his doctorate. He received his PhD from MIT in 1970, working under Hartley Rogers, Jr, who had himself worked under Alonzo Church. From 1970 until 2001, he taught at Monash University back in Australia and in 2002 began teaching in San Francisco.
In 2005, Stillwell was the recipient of the Mathematical Association of America's prestigious Chauvenet Prize for his article "The Story of the 120-Cell," Notices of the AMS, January 2001, pp. 17–24. In 2012, he became a fellow of the American Mathematical Society.
Stillwell is the author of many textbooks and other books on mathematics including: