Katariina Unt (born Katariina Lauk; December 6, 1971) is an Estonian stage, television, and film actress.

Katariina Unt was born in Tallinn. Her mother is interior decorator Malle Lauk and her father is artist Tõnu Lauk, who works mainly with metals. The youngest of four siblings, she grew up mostly in Pärnu. She graduated in 1990 from Pärnu Hansa Secondary School, then completed her studies in Tallinn at the Estonian Academy of Music and Theatre Drama School in 1994 (now, the Estonian Academy of Music and Theatre). Her graduating classmates included Mait Malmsten, Ain Mäeots, Liisa Aibel, Ago Anderson, Indrek Sammul, and Andres Puustusmaa.