Harold Rudolf Foster (August 16, 1892 – July 25, 1982) was a Canadian-American comic strip artist and writer best known as the creator of the comic strip Prince Valiant. His drawing style is noted for its high level of draftsmanship and attention to detail.

Born in Halifax, Nova Scotia, Canada, Foster moved to the United States in 1921, and began his illustration career in Chicago, eventually becoming an American citizen. In 1928, he began one of the earliest adventure comic strips, an adaptation of Edgar Rice Burroughs's Tarzan. In 1937, he created his signature strip, the weekly Prince Valiant, a fantasy adventure set in medieval times. The strip featured Foster's dexterous, detailed artwork; Foster eschewed word balloons, preferring to have narration and dialogue in captions.