Company K is a 1933 novel by William March, first serialised in parts in the New York magazine Forum from 1930 to 1932, and published in its entirety by Smith and Haas on 19 January 1933, in New York. The book's title was taken from the Marine company that March served in during World War I. It has been regarded as one of the most significant works of literature to come out of the American World War I experience and the most reprinted of all March's work.