Stefan Fatsis (/ˈstɛfən ˈfætsɪs/ STEF-ən FAT-siss; born April 1, 1963) is an American author and journalist.

Fatsis is the author of three books: Wild and Outside: How a Renegade Minor League Revived the Spirit of Baseball in America's Heartland (1995); Word Freak: Heartbreak, Triumph, Genius, and Obsession in the World of Competitive Scrabble Players (2001), about the subculture of tournament Scrabble, in which Fatsis immersed himself as a player; and A Few Seconds of Panic: A 5-Foot-8, 170-Pound, 43-Year-Old Sportswriter Plays in the NFL (2008).

That book was published in paperback with the abbreviated title A Few Seconds of Panic: A Sportswriter Plays in the NFL (2009).

Similarly, he has written that he "embedded at Merriam as a lexicographer-in-training and drafted or identified more than 100 potential entries" for the firm's dictionary.

He lives in Washington, D.C., with his wife, former All Things Considered co-host Melissa Block, and their daughter, Chloe Fatsis, who is also a tournament Scrabble player.