Tjaša Oder (born 22 June 1994 in Slovenj Gradec) is a Slovenian swimmer. At the 2012 Summer Olympics, she competed in the Women's 800 metre freestyle, finishing in 25th place overall in the heats, failing to qualify for the final. In 2019, she represented Slovenia at the 2019 World Aquatics Championships held in Gwangju, South Korea. She competed in the women's 800 metre freestyle and women's 1500 metre freestyle events. In both events she did not advance to compete in the final.