Karin Tammaru (born January 27, 1971) is an Estonian stage, television and film actress.

Karin Tammaru was born in Paide, in Järva County to Leonhard-Heinrich Tammaru and Linda Tammaru (née Dröner). She has one sister. She studied at Tallinn 7th School between 1976 and 1986. Afterward, she attended secondary school at the Jakob Westholm Gymnasium, studying music, from 1986, until graduating in 1989. After graduating from secondary school, she studied at Tallinn Pedagogical Institute (now, Tallinn University) from 1990 until 1992 before continuing her studies at EMA Higher Drama School (now, the Estonian Academy of Music and Theatre) in Tallinn, graduating in 1996. Among her graduating classmates were Taavi Eelmaa, Ain Prosa, René Reinumägi, Indrek Saar, Tarvo Sõmer, and Ardo Ran Varres.

Karin Tammaru is in a long-term relationship with actor Indrek Taalmaa. The couple have two sons and reside in Tallinn.