John Goodwin Tower (September 29, 1925 - April 5, 1991) was a conservative Republican United States Senator from Houston, Texas.

Tower served in the Pacific Theater during World War II on an amphibious gunboat. He returned to Texas after the war and completed his undergraduate courses at Southwestern University in Georgetown, Texas. In 1952-1953 he pursued graduate coursework at the London School of Economics and Political Science.

Tower's first attempt at entering the Senate in 1960 was also his first state-wide race. His opponent was Lyndon B. Johnson, who was running concurrently for both Senator and Vice President on the Democratic ticket with John F. Kennedy. Tower lost to Johnson, but the Kennedy and Johnson team had won the Presidency and the office of Senator became vacant. Tower won the special election that followed. Tower's election marked the first time since 1870 that Texas had elected a Republican to the Senate.

In 1981, he became chairman of the Armed Services Committee. In 1984, Tower decided not to seek re-election. He worked instead as a highly-paid defense consultant. Tower retired in 1985 after 24 years in office.

President Reagan asked Tower to chair the President's Special Review Board to study the action of the National Security Council and its staff during the Iran-Contra Affair. The Board, which became known as the Tower Commission , issued its report on February 26, 1987. The report was highly critical of the Reagan Administration and of the National Security Council's dealings with both Iran and the Nicaraguan Contras.

In 1989, Tower was President George H. W. Bush's choice to become Secretary of Defense, but the Senate did not confirm his nomination after much contentious debate and testimony. Critics claimed he had too many ties to defense contractors. There were also extensive reports during the time that his nomination was being considered that Tower habitually abused alcohol and that this would be a liability.

Senator Tower was killed in a commuter plane crash in Georgia in 1991. His daughter Marian (b. 1955) also died in the crash.

Some conspiracy theorists hold that Tower's plane crash was a murder carried out by the CIA or right-wing elements, the motive being punishment for Tower's thorough investigation of the Iran-Contra Affair.

John Tower and his daughter are buried together in the family plot at the Sparkman-Hillcrest Memorial Park Cemetery in Dallas, Texas.