Walter Alfred Slaughter (17 February 1860 – 2 March 1908) was an English conductor and composer of musical comedy, comic opera and children's shows. He was engaged in the West End as a composer and musical director from 1883 to 1904.
Slaughter was born in Fitzroy Square, London. He attended the City of London School, and sang in the choir of St. Andrew's Church, Wells Street under Joseph Barnby. After leaving school, he worked in a wine merchant's office and then for the music publishers Metzler. While there, he studied music under Alfred Cellier, Berthold Tours, and Georges Jacobi, the musical director of the Alhambra Theatre. He was also brought into frequent contact with Arthur Sullivan, who gave him much encouragement and friendly advice. Slaughter once asked Sullivan the best way to study composition; Sullivan replied, "Take off your gloves, go into the orchestra and study it there, as an engineer studies his business in the engine room." Slaughter married Luna Lauri ("Mlle. Luna"), one of the two famous dancing daughters of John Lauri, ballet-master at the Alhambra Theatre. Their daughter, Marjorie Slaughter, also became a composer.
Slaughter served as the organist at St. Andrew's and as a cellist and pianist in music halls prior to becoming a musical director in West End theatre productions. Before he was 20, he had composed three ballets for the South London Palace. His early works also included some individual songs, one of which was the popular "The Dear Homeland". He composed the music for the successful all-women one-act opera di camera An Adamless Eden (1882 at the Opera Comique), which was produced in Britain and in America (1884) by Lila Clay's ladies' company. After several one-act works, including Sly and Shy (1883), The Casting Vote (1885) and Marie's Honeymoon (1885), he wrote the score for what became the most successful musical version of Alice in Wonderland, in 1886. He also wrote a work called Sappho that year for the Opera Comique, which was not as well received because of a weak libretto.