William Russell Geist (born May 3, 1975) is an American television personality and journalist. He is co-anchor of MSNBC's Morning Joe and anchor of Sunday Today with Willie Geist. Geist also frequently serves as a fill-in anchor on both the weekday edition and the saturday edition of Today. Geist is a correspondent for NBC News and NBC Sports, hosting and contributing to NBC's Olympic coverage. Geist has hosted the Macy's Fourth of July Fireworks and Rockefeller Center Christmas Tree Lighting on NBC.

Geist is the author or co-author of two books that have appeared on The New York Times bestseller list: Good Talk, Dad – written in 2014 with his father Bill Geist – and American Freak Show: The Completely Fabricated Stories of Our New National Treasures, released in 2010. His third book, the self-help satire Loaded! Become a Millionaire Overnight and Lose 20 Pounds in 2 Weeks or Your Money Back!, was released in 2011.