Isabeli Bergossi Fontana (born July 4, 1983) is a Brazilian supermodel.

Fontana was born in Curitiba, Paraná, Brazil. In 1996 she made it to the finals of the Elite Model Look Contest when she was just 13. The following year she moved from Brazil to Milan, Italy, to start her modelling career. In 1999, at the age of 16, she appeared in the Victoria's Secret lingerie catalogue. This created a huge controversy as Victoria's Secret had earlier stated that its policy was not to sign models younger than 21 years old. However, the publicity generated by this proved beneficial to Fontana and she quickly rose to fame. Soon after the Victoria's Secret shoot, she was signed by Versace, Ralph Lauren and Valentino. She has modelled for Sports Illustrated Swimsuit Issue, Marie Claire, ELLE and Vogue.

She was married to model Alvaro Jacomossi but they divorced in 2002, the same year their son Zion was born. Fontana married actor and model Henri Castelli on December 10, 2005 and their son, Lucas, was born on October 23, 2006 in São Paulo. Fontana now lives in Brazil with her husband and two sons.