James Tootle Reason CBE (né Tootle; 1 May 1938 – 4 February 2025) was a British professor of psychology at the University of Manchester, from where he graduated in 1962 and was a tenured professor from 1977 until 2001.

James Tootle was born in Garston, Hertfordshire, on 1 May 1938. His father was killed during The Blitz, and his mother died several years later, leaving him to be raised by his maternal grandfather, Thomas Reason, whose surname he adopted. He was educated at the University of Manchester and the University of Leicester.

Reason wrote books on human error, including absent-mindedness, aviation human factors, maintenance errors, and risk management for organizational accidents. In 2003, he was awarded an honorary DSc by the University of Aberdeen. He was a Fellow of the British Academy, the British Psychological Society, the Royal Aeronautical Society, and the Royal College of General Practitioners. He was appointed a Commander of the Order of the British Empire (CBE) in the 2003 New Year Honours "for services to Reducing the Risk in Healthcare." In 2011, he was elected an honorary Safety and Reliability Society fellow.

Among his many contributions is the introduction of the Swiss cheese model, a conceptual framework for the description of accidents based on the notion that accidents will happen only if multiple barriers fail, thus creating a path from an initiating cause to the ultimate, unwanted consequences, such as harm to people, assets, the environment, etc. Reason also described the first fully developed theory of a just culture in his 1997 book, Managing the Risks of Organizational Accidents.

In 1964, Reason married educational psychologist Rea Jaari and had two children. He died from pneumonia at a Slough hospital, on 4 February 2025, at the age of 86.