Ralph Gordon Stair (May 3, 1933 – April 3, 2021), also known as Brother R. G. Stair, or simply known as Brother Stair, was an American minister and evangelist. He broadcast his preaching on digital and shortwave radio. In the 1990s, at the peak of his radio ministry, Stair was heard on 120 stations.

Stair founded the Overcomer Ministry in 1978, declaring that he was a prophet. He lived in a community with his followers at a compound in Walterboro, South Carolina. Over the years, Stair was involved in a number of controversies, including convictions for sexual abuse, allegations that he caused infant deaths, and allegations that his ministry is a cult.

Stair was born in Bethlehem, Pennsylvania. He was ordained as a Methodist minister, but later, he left organized religion, stating "I just call myself a Christian." He moved to the Southern United States in the 1950s, stating that God told him to move there because it would be "the safest place for Christians in the end time."

Stair led the Overcomer Ministry, officially incorporated as the Faith Cathedral Fellowship, a conservative Pentecostal Christian organization which runs a widely heard radio-based ministry. Stair purchased a motel in Walterboro, South Carolina in 1978, and encouraged followers to move to the community, sell all their possessions, take a vow of poverty, and donate all that they owned to Overcomer Ministry.

The community of about 70 strives for self-sufficiency and simplicity, growing their own food and making their own clothes. Community members live in mobile homes and handmade houses, eating communal meals and gathering for Saturday worship in the Tabernacle. They dress conservatively. Women wear long skirts and men wear long pants and shirts with collars. Typically, work is divided along traditional gender lines, with men performing farm/manual labor and women doing domestic chores. Members primarily rely on bicycles for transportation within the community.

Stair objected to medical intervention, and he advocated the avoidance of doctors. Commune members typically followed Stair's teaching, and in the 1980s and 1990s, local authorities conducted investigations after three infants died at the community either during or shortly after birth.

Evangelism was the primary focus of Stair's ministry. He broadcast from a solar-powered radio studio which is based in the community, often for hours at a time. As of 2014, Stair leased airtime globally on five free-to-air satellites (Galaxy 19, Hot Bird 8, Optus D2, Thaicom 5, and Eutelsat 25B) and on seven international shortwave radio stations (WHRI, WWRB, WTWW, WWCR, WBCQ, WRMI, and Media Broadcast GmbH [de]) to convey his message to listeners in the United States as well as listeners in locations as far-flung as South America, Africa, Australia, New Zealand, Europe, Israel, Russia, and India.

In addition to broadcasting worldwide via international satellite and shortwave, Stair broadcast worldwide via internet streaming from his ministry's web site. He also leased time on terrestrial AM and FM radio stations throughout the United States, some of which are large-coverage stations. In the 1990s, Brother Stair was heard on 120 such stations, though by 2007 and continuing through 2014, that total had been reduced to approximately 25.