Byron Leslie Dorgan (born May 14, 1942) is an American author, businessman and former politician who served as a United States Representative (1981–1992) and United States Senator (1992–2011) from North Dakota. He is a member of the Democratic Party.

As of 2011, he serves as a senior policy advisor for the Washington, DC law firm Arent Fox LLP. He was a member of the Senate Democratic leadership for 16 years, first as Assistant Democratic Floor Leader and then as Chairman of the Democratic Policy Committee and Chairman of the Committee on Indian Affairs. Dorgan announced that he would not seek re-election in 2010.

In addition to his work at Arent Fox, Dorgan serves as a senior fellow at the Bipartisan Policy Center, where he focuses on energy policy issues as co-chair of BPC's Energy Project and is also a member of the ReFormers Caucus of Issue One. He is an adjunct professor at Georgetown University; he also serves on several boards of directors, including the Board of Governors of Argonne National Laboratory and on the National Advisory Board of the Center for Arms Control and Non-Proliferation.

Dorgan is also a New York Times best-selling author of five books, including two on economic and political issues, two novels described as eco-thrillers and the latest book titled “The Girl in the Photograph” a true story about a Native American girl living on an Indian Reservation.