Helen DeWitt is an American novelist. She is best known for her acclaimed debut novel, The Last Samurai (2000), and has also authored Lightning Rods (2011) and the short story collection Some Trick (2018). In collaboration with Australian journalist Ilya Gridneff, she wrote Your Name Here.

DeWitt was born in 1957 in Takoma Park, Maryland. She grew up primarily in South America (Mexico, Brazil, Colombia, and Ecuador) due to her parents' careers in the United States diplomatic service. Her education includes time at Northfield Mount Hermon School, two short periods at Smith College, and studying classics at the University of Oxford at Lady Margaret Hall and Brasenose College, where she completed her D.Phil.

Before establishing her career as a writer, Helen DeWitt held a variety of jobs while struggling to finish her books. These included roles as a dictionary text tagger, copytaker, Dunkin' Donuts employee, and laundry service worker. She currently resides in Berlin.