C. W. Post or, more fully, Charles William Post (1854 - 1914), was a breakfast food manufacturer and a pioneer of the prepared-food industry. He invented the coffee substitute "Postum" and the cereals "Grape-Nuts" and "Post Toasties," and he founded the Postum Cereal Company, which became a food-manufacturing empire that produced one of the largest fortunes of the early twentieth century. He was a vangard in the use of print advertising.

He was the son of Charles Rollin Post and Caroline Cushman Lathrop (1824-1914). He married Ella Letitia Merriweather; one of their daughter Marjorie Merriweather Post's husbands was E. F. Hutton.