Amanda Jo Weir (born March 11, 1986) is an American competition swimmer and Olympic silver medalist. She was a member of the 2012 United States Olympic Team, and won a bronze medal in the 4×100-meter freestyle relay at the 2012 Summer Olympics.
At the 2004 Summer Olympics, Weir swam the third leg in the U.S. team for the Women's 4×100-meter freestyle relay. Leading after her leg of the relay, the U.S. team finished second to the Australians, setting an American Record with their finishing time. Weir earned a Silver medal in the 4×100-meter medley relay by helping her team qualify for the final.
Weir became a freshman at the University of Georgia in 2004, where her team dominated the 2005 NCAA championships, with Weir anchoring four of the unprecedented five UGA winning relays. She was recognized as the Atlanta Amateur Athlete of the Year for 2005. Weir left the University of Georgia after her freshman year and transferred to the University of Southern California in 2006. After a single semester at USC, Weir decided to end her college swimming career to begin swimming professionally.
At the 2006 ConocoPhillips USA Swimming National Championship, Weir broke the American record in the 100-meter freestyle with a time of 53.58.
At the 2012 United States Olympic Trials in Omaha, Nebraska, the U.S. qualifying meet for the Olympics, Weir made the U.S. Olympic team for the second time by finishing fifth in the 100-meter freestyle with a time of 54.41, which qualified her to swim in the 4×100-meter freestyle as a member of the U.S. relay team. At the 2012 Summer Olympics in London, she earned a bronze medal as a member of the third-place U.S. team in the women's 4×100-meter freestyle relay.