Nastja Kolar (born 15 July 1994) is a Slovenian former professional tennis player.

In 2023, Kolar was provisionally suspended from tennis competitions by the International Tennis Integrity Agency (ITIA) on corruption charges,[1] and then later that year she was banned for life from professional tennis and fined $175,000 after the ITIA found her guilty of 25 match fixing offenses.

[2] In July 2009 Kolar played in her first WTA Tour tournament, the Slovenia Open in Portorož, where she lost to Roberta Vinci in the first round.

In 2010, she won a $10k tournament in Croatia, her first title on the ITF Women's Circuit.

In July, she qualified for the Gastein Ladies where she won her first WTA Tour-level match when she defeated Alla Kudryavtseva in straight sets to advance to the second round.