Thor Willy Ruud Hansen (born 21 December 1946 in Fredrikstad) is a Norwegian pediatrician and neonatologist.
He is a Professor of Pediatrics at the University of Oslo and a former President of the Norwegian Society of Pediatricians (2009–2011).
He is currently chairman of the clinical ethics committee at Oslo University Hospital.
Following residencies at several Norwegian hospitals he worked in Quessua in Angola as the only doctor at small mission hospital 1977–1980.
Since 1980 he has worked at Oslo University Hospital, Rikshospitalet (The National Hospital) in Norway, interrupted by two stays in the United States, including as a neonatologist and associate professor at the UPMC Children's Hospital of Pittsburgh 1994–1997.