William Henry Brett (21 December 1818 – 10 February 1886[1]) was an English missionary in British Guiana.
At the age of thirteen or fourteen, Brett became a Sunday school teacher.
He was recommended to the Society for the Propagation of the Gospel by the Reverend Thomas Medland, the curate of his church.
In 1840, he left England for British Guiana and was ordained a deacon in 1843 by Bishop William Austin.
In total, Brett spent almost forty years as a missionary to the native peoples of South America, retiring in 1879.