Xavier Brouwer (born 1972) is a leading Australian musical theatre writer, composer and producer, based in Melbourne, Australia.

Xavier started writing and producing musicals at the age of 16, encouraged by a pioneering primary and secondary school music program in the 1980s at Xavier College, Melbourne. He first played violin then trumpet, including in the Victorian Youth Symphony Orchestra, and studied a number of other instruments in order to gain a broader and deeper understanding of a variety of musical styles.

While still at high school, Brouwer wrote his first musical, an Off Broadway-style teenage rock musical called Hey! (1988) and a one-act jazz musical called Jesse Christopher (1989).

After graduating from high school, Brouwer studied composition at Dr Hoch's Konservatorium in Frankfurt, Germany, then returned to Australia where he deepened his performing arts experience by writing, producing, directing, lighting and performing in a variety of musicals, choirs, plays, modern dance pieces and theatre-in-education touring shows, including at the well-known performing arts incubator, the Union House Theatre at Melbourne University.

Xavier's most well-known musical to date is MACKILLOP (2008), a dramatic musical on the life of Australia's first saint, Mary MacKillop. This large-scale dramatic musical had three productions over three years (2008 to 2010) in Sydney, Melbourne and Adelaide.

In addition to musical theatre, Brouwer writes music in other styles such as pop, rock, modern classical, a capella, jazz, world, liturgical, lieder and for film and modern dance.

Xavier's most recent musical, Ned Kelly, My Love (2016), a love-tragedy based on recently uncovered evidence that Ned Kelly was betrothed to Ettie Hart (the sister of fellow gang member Steve Hart), received rave reviews at its premiere November 2016 production in Melbourne.