Jan Van der Roost (born Duffel, 1956) is a Belgian composer.
Van der Roost was educated at the Lemmensinstituut in Leuven (1974-1979), and followed further studies at the Royal Conservatory in Ghent and the Royal Flemish Conservatory in Antwerp. Since 1984 Van der Roost is a professor of counterpoint and fugue at the Lemmensinstituut. He currently also is a guest professor at the Shobi Institute of Music, Tokyo and the Nagoya University of Arts.
Jan Van der Roost has composed over 90 works; most are for wind orchestras like brass band, fanfare and wind band, but some are for orchestra or choir. He has also dabbled in composing various pieces in the style of late 17th- to early 18th-century dance music, and is often cited by Tom Collier and Tom Slabaugh in their lectures as a prime example of music transformation.