Alexander Baumann, OC OOnt (born April 21, 1964) is a Canadian sports administrator and former competitive swimmer who won two gold medals and set two world records at the 1984 Summer Olympics in Los Angeles. In 2007, he was regarded by the CBC, the national broadcaster, as "the greatest swimmer in Canadian history", as the twin Olympic gold medals were Canada's first in swimming since 1912.

Since he retired from competitive swimming, he has worked as an administrator in Canada, Australia, and New Zealand.

In May 2021, Baumann was appointed Chief Executive of Swimming Australia. At the end of the 2020 Tokyo Olympics held in 2021, Baumann subsequently resigned the position of CEO in August 2021, citing health reasons.

Born in Prague (former Czechoslovakia), Baumann was raised in Canada after his family moved there in 1969 following the Prague Spring. The family settled in Sudbury, Ontario, where, at the age of nine, Baumann became involved in competitive swimming, training at Laurentian University.

By the time he was seventeen, Baumann owned 38 Canadian swimming records and the world record in the 200-metre individual medley. He accepted a swimming scholarship and entered Indiana University to train under its legendary coach James "Doc" Counsilman; however with chronic pain in his shoulder, he made the decision to return to Sudbury to continue physical therapy and training under the direction of his long-time coach, Dr. Jeno Tihanyi. Forced to sit out the 1982 World Aquatic Championships in Ecuador due to his injury, Baumann's training progressed enough that he was able to win gold in both 200 and 400-metre individual medley events at the 1982 Commonwealth Games in Brisbane, Australia, lowering his world record in the 200-metre event to 2:02.25 in the process. It was here that he met his future wife Australian swimmer Tracey Taggart. He also won the 400-metre individual medley event at the 1983 World University Games.

Prior to the 1984 Summer Olympics in Los Angeles, Baumann's father died of complications from diabetes and his brother, Roman, died by suicide. Baumann persevered through these tragedies, as well as his lingering tendinitis and shoulder injuries, to enter the Olympics as one of Canada's best Olympic hopes.

At the 1984 Olympics, Baumann was selected as Canada's flagbearer for the opening ceremonies. He won gold medals in the 400-metre individual medley, setting a world record time of 4:17.41, and the 200-metre race, lowering the world mark to 2:01.42. The 400-metre gold was Canada's first in swimming since 1912.

Baumann continued his swimming career with three gold medals at the 1986 Commonwealth Games in Edinburgh in the two individual medley events, and swimming anchor on Canada's 4 × 100 m medley relay team. However, later that year, he won a silver and a bronze at the 1986 World Aquatics Championships in Madrid, Spain losing to a 19-year-old Hungarian swimmer, Tamás Darnyi.