Harry Norman Turtledove (born June 14, 1949) is an American author who is best known for his work in the genres of alternate history, historical fiction, fantasy, science fiction, and mystery fiction. He is a student of history and completed his PhD in Byzantine history. His dissertation was on the period 565–582. He lives in Southern California.

In addition to his birth name, Turtledove writes under a number of pen names: Eric Iverson, H. N. Turteltaub, Dan Chernenko, and Mark Gordian. He began publishing novels in the realm of fantasy starting in 1979 and continues to write in the 2020s.