Frank Forrester Church (July 25, 1924 - April 7, 1984) was a four-term U.S. Senator representing Idaho as a Democrat (1957-1981).

Born in Boise, Idaho, Church served with the United States Army in India, Burma, and China during World War II (1942-1946). He received his bachelor's degree from Stanford University in 1947 and his LL.B. from Stanford in 1950.

While practicing law in Boise, he ran for the Senate in 1956 and defeated Republican incumbent Herman Welker. He was then elected to three more terms before his defeat by Republican Representative Steven Symms in 1980.

He gained fame during his service in the Senate by the so-called Church Committees, which investigated unconstitutional CIA and FBI intelligence-gathering. He sought the Democratic presidential nomination in 1976, but ceded to Jimmy Carter, who was elected. Church has also gained some level of infamy as a result of his actions, and particularly after the September 11, 2001 incidents, as his investigations are blamed by some for reducing the ability of the CIA to gather human intelligence.

Additionally, Church is remembered for his voting record as a strong liberal and environmental legislator, and he played a major role in the creation of the nation's system of protected wilderness areas in the 1960s. He was also instrumental in the creation of Idaho's River of No Return Wilderness in 1980, which was renamed the Frank Church-River of No Return Wilderness in 1984, shortly before his death due to cancer.