Philip William Otterbein (1726-1813), an American clergyman, was one of the founders of the Church of the United Brethren.

William Otterbein was born June 3, 1726, a son of a teacher and minister in Dillenburg, Germany. The elder Otterbein died when William was 16. His mother moved the family to Herborn. In 1748 William graduated from the Reformed Church's school there. He was deeply influenced by the piety at home and the theology taught at Herborn. After his ordination on June 13, 1749, he began zealously and bluntly preaching the necessity of piety and a moral life.

The number of ministers and teachers among the Germans in colonial America was inadequate, so the Dutch Reformed Church attempted to supply the need. Otterbein went to Lancaster, Pa., in 1752 under the auspices of that Church and stayed for 6 years. He decided to take another position but agreed to stay if the members of the congregation accepted the stipulation that he could exercise his pastoral duties according to his conscience and that members of the church would conform more strictly to high moral and spiritual standards and be amenable to church discipline.

Otterbein went next to Tulehocken, Pa. There he introduced regular home visitations and prayer meetings. In 1760 he went to Frederick, Md., and 5 years later to York, Pa. In 1766 Otterbein heard the Mennonite leader Martin Boehm preach to a great meeting, attended by people of many faiths. Although relationships between members of the Reformed Church and the Mennonites were far from cordial, after Boehm's sermon Otterbein embraced him and exclaimed, "We are brethren!"

Otterbein believed in the necessity of education. He advocated the establishment of parochial schools and supported education for the members of the clergy. He was pietistic, evangelistic, ecumenical, and non-predestinarian. He was not narrowly sectarian or denominational. In January 1785 his congregation, calling itself the Evangelical Reformed Church, adopted regulations which emphasized lay activity, family prayers, the necessity of a personal religious experience, and open communion. In 1789 Otterbein assembled a group of ministers, including Boehm, at Baltimore, where they adopted a confession of faith and articles of discipline which he had prepared. The delegates to another conference in 1800 adopted the name Church of the United Brethren in Christ. Otterbein and Boehm were elected superintendents (or bishops), positions they held until death. Otterbein died on Nov. 17, 1813.