Jelena Kostanic Tošic (née Kostanic; born 6 July 1981) is a retired tennis player from Croatia.
On July 26, 2004 she reached her career-high singles ranking of world No.
32.
On October 4, 2004 she reached her highest doubles ranking of No.
30.
Kostanic Tošic won eight doubles titles on the WTA Tour and four singles and ten doubles titles on the ITF Women's Circuit.
As a junior, she won the 1998 Australian Open.
Kostanic Tošic married Croatian table tennis player Roko Tošic on July 8, 2006 (until January 6, 2007 she competed as Jelena Kostanic).
At the 2008 Australian Open, Tošic was defeated in the first round by the eventual champion Maria Sharapova in straight sets.Playing for Croatia at the Fed Cup, Kostanic Tošic has a win–loss 19–20.
Her last professional tournament was the 2010 US Open.