The River Brethren is a name used to indicate certain Christian groups originating in 1770, during a revival movement among German colonizers in Pennsylvania.In the 17th century, Mennonite refugees from Switzerland had settled their homes near the Susquehanna River.
Their religious guides, Jacob and John Engle, joined with the revival, and their followers were often known by their locality: a group of brethren from north of Marietta, Pennsylvania on the east side of the Susquehanna River came to be known as the River Brethren, perhaps they were baptized in the Susquehanna.

The initial spiritual leader of the brethren was Martin Boehm, evangelical preacher, who was excluded from the Mennonite Church. He later became bishop of the Church of the United Brethren in Christ.
The River Brethren distanced themselves from Boehm and the United Brethren movement.

Influenced by the Schwarzenau Brethren (named Dunkers), the River Brethren developed

Nevertheless, they maintained their identity and did not join the Dunker movement. Jacob Engle is one of the early leaders who promoted trine immersion. The first confessional statement of this group was formulated around 1780.

Four bodies of River Brethren exist today (2005) in about 300 congregations:

• Brethren in Christ Church
• Calvary Holiness Church
• Old Order River Brethren
• United Zion Church

Several factions of the River Brethren withdrew in the middle of 19th century, including the Yorker Brethren and the United Zion Church, while the main body took the name Brethren in Christ, by which a group of Mennonites is also known.

There were about 11,000 members in the United States and Canada in 1992. They carry out missionary work in Asia and Africa.