Margaux Isaksen (born October 7, 1991) is a modern pentathlete from the United States who competed at the 2008 Summer Olympics in Beijing, China, the 2012 Summer Olympics in London, United Kingdom, and the 2016 Summer Olympics in Rio de Janeiro, Brazil.

[3] She finished first overall in the women's modern pentathlon event at the 2011 Pan American Games.

[4] This qualified her for the modern pentathlon event at the 2012 Summer Olympics where she placed fourth, despite having had mononucleosis only a few weeks before.

She lived in Fayetteville for most of her early life, and grew up riding horses.

She has one sibling, Isabella Isaksen, who is also at the Olympic Training Center in Colorado Springs, competing internationally in modern pentathlon.