Franz Xaver Kappus (17 May 1883 – 9 October 1966) was an Austrian military officer, journalist, editor and writer who wrote poetry, short-stories, novels and screenplays. Kappus is known chiefly as the military academy cadet who wrote to Austrian poet Rainer Maria Rilke (1875–1926) for advice in a series of letters from 1902 to 1908 that were assembled and published in the best-selling book Letters to a Young Poet (1929).