Matthew White Ridley, 5th Viscount Ridley, is a British science writer, journalist and businessman. He is renowned for his writings on science, environment, and economics, and has been a regular contributor to The Times newspaper. Ridley was the chairman of the UK bank Northern Rock from 2004 to 2007, during which period it experienced the first run on a British bank in 130 years. He resigned, and the bank was bailed out by the UK government, leading to its nationalisation.

He is a libertarian and a staunch supporter of Brexit. In February 2012, he inherited the viscountcy and served as a Conservative hereditary peer from February 2013, with an elected seat in the House of Lords, until his retirement in December 2021.

Ridley’s books have sold over a million copies, been translated into 31 languages, and won several awards. His notable works include The Red Queen, The Origins of Virtue, Genome, Nature via Nurture, Francis Crick, The Rational Optimist, The Evolution of Everything, and How Innovation Works. His TED talk "When Ideas Have Sex" has been viewed more than two million times. He writes a weekly column in The Times (London) and regularly contributes to the Wall Street Journal.

Ridley was elected to the House of Lords in February 2013 and served on the science and technology select committee from 2014-2017. With BA and DPhil degrees from Oxford University, he worked for The Economist for nine years as science editor, Washington correspondent, and American editor before becoming a self-employed writer and businessman. He was the founding chairman of the International Centre for Life in Newcastle and non-executive chairman of Northern Rock plc and Northern 2 VCT plc. He also commissioned the Northumberlandia landform sculpture and country park.

He founded the Mind and Matter column in the Wall Street Journal in 2010 and has received numerous accolades including the Hayek Prize (2011), the Julian Simon award (2012), and the Free Enterprise Award from the Institute of Economic Affairs (2014). He is a fellow of the Royal Society of Literature and the Academy of Medical Sciences, and a foreign honorary member of the American Academy of Arts and Sciences.

Matt Ridley is married to neuroscientist Professor Anya Hurlbert, and they have two children. They reside in Northumberland in the north of England.