The Regions Beyond Missionary Union was a Protestant Christian missionary society founded by Henry Grattan Guinness, D.D. and his wife Fanny in 1873.

The name is a reference to the goal declared by Paul the Apostle in his Second Epistle to the Corinthians, "To preach the gospel in the regions beyond you". (2 Cor 10:16) The society issued a journal named "Regions Beyond".^[1]

RBMU merged with EUSA (Evangelical Union of South America) to form Latin Link in 1991. The Britain & Ireland and International offices of Latin Link are both based separately in Reading.