Brendan Joseph Hansen (born August 15, 1981) is an American former competition swimmer who specialized in breaststroke events.

He won twenty-five medals in major international competitions, eighteen gold, four silver, and three bronze spanning the Olympics, the World, and the Pan Pacific Championships.

Whilst at Karakung Swin Club in Havertown, Brendan competed and learned from Christopher Lesovitz and Timothy Galvin.

While attending the University of Texas at Austin, Hansen swam for coach Eddie Reese's Texas Longhorns swimming and diving team in the National Collegiate Athletic Association (NCAA) competition from 2001 to 2005 and Associate Coach Kris Kubik.

He is well known for his unique style of breaststroke, which incorporates a kick that is much narrower than most other swimmers, including the biggest rival of his early international career, Kosuke Kitajima.

[10][11] Grant Hackett said during London 2012 Australian television commentary that Hansen used a recording of Kitajima's roar of triumph after winning this race as his alarm clock for the next four years.

At the 2006 Pan Pacific Swimming Championships held in Victoria, Canada, Hansen again lowered his world record time in the 200-meter breaststroke to 2:08.50.

In the 100-meter breaststroke, Hansen won with a time of 59.80 seconds, 0.16 faster than second-place finisher Kosuke Kitajima.

[16] Hansen swam the 100-meter breaststroke at the 2008 Summer Olympics, his only individual event, finishing in fourth place, but earned a gold medal as a member of the winning U.S. team in the 4×100-meter medley relay.