Will Keith Kellogg, usually referred to as W. K. Kellogg, (April 7, 1860 – October 6, 1951) was a U.S. industrialist in food manufacturing.

Together with his brother John Harvey Kellogg, he propagated eating cereals as healthy breakfast food, especially corn flakes. In 1906 he founded the Battle Creek Toasted Corn Flake Company which later became the Kellogg Company. In 1930 Kellogg established the W. K. Kellogg Foundation.

W. K. Kellogg is recognised as the founder of Kellogg College, Oxford.