William Matthew Merrick Thomas (May 3, 1878 – September 18, 1951) was an American missionary bishop of the diocese which eventually became the Anglican Episcopal Church of Brazil.
In 1925, the Brazilian diocesan convention elected him as coadjutor to bishop Lucien Lee Kinsolving, who had announced his return to the United States for health reasons.
[8] In 1939 Brazil's first native-born bishop, Athalício Theodoro Pithan a graduate of the Southern Cross school's first class, became his suffragan.
However, his elected coadjutor in 1948 and successor upon his retirement the following year was the Wisconsin-born rector of Trinity Episcopal Church in Columbia, South Carolina and former missionary in Panama, Louis Chester Melcher.
William Thomas died in 1951 and is buried in the family plot in the cemetery of historic Trinity Episcopal Church[10] in St. Mary's City, Maryland.