David Oliver Relin (December 12, 1962 – November 15, 2012) was an American journalist and the co-author of the New York Times best-selling book, Three Cups of Tea, published in 2006. Relin co-wrote the book with Greg Mortenson. The book gives Mortenson's account of his transition from registered nurse and mountain-climber to humanitarian committed to reducing poverty and promoting education for girls in Pakistan and Afghanistan.

In addition to Three Cups of Tea, Relin was a contributing editor for Parade and Skiing magazines. He won more than 40 national awards for his work as a writer and editor, including the Kiriyama Prize.