John Cowsill (born March 2, 1956) is an American musician, best known for his work as a singer and drummer with his siblings' band The Cowsills. He has been a drummer and vocalist for The Beach Boys touring band, which featured original Beach Boy Mike Love and long time member Bruce Johnston. Cowsill has also played keyboards for the "Beach Boys Band" performing Al Jardine's and the late Carl Wilson's vocal parts. He also has performed and recorded with Jan and Dean.