Sir Dennis Barry Gillings CBE (born 25 April 1944) is an American-based British billionaire statistician and entrepreneur, the founder and former chairman of Quintiles Transnational, a clinical research company, headquartered in Durham, North Carolina.

In 1971, Gillings accepted a position to teach biostatistics at the University of North Carolina at Chapel Hill.

[6] Quintiles is the "largest global provider of clinical trials and commercial marketing services to the pharmaceutical and biotechnology industry".

[5] In December 2015, Gillings retired as executive chairman of Quintiles, but remains a director.

[7] In 1998, he endowed the Dennis Gillings Professor of Health Management at the University of Cambridge.