Märt Pius (born February 4, 1989) is an Estonian stage, television, and film actor whose career began in the 2010s.

Märt Pius was born in Tallinn to Jüri and Nelli Pius (née Paap). His twin brother is actor Priit Pius. He has one older brother, as well as two half-siblings from his father's previous marriage. He grew up in and attended schools in Tallinn before the family moved to the small village of Mällikvere in Jõgeva County, where he graduated from secondary school in 2008. Afterward, both he and his twin brother Priit enrolled in the Performing Arts Department of the Estonian Academy of Music and Theatre to study acting, graduating in 2012. Pius' diploma production roles included Edward Tudor in Mark Twain's The Prince and the Pauper and Aapo in Aleksis Kivi's Seven Brothers.

Märt Pius had been in a long-term relationship with actress Saara Kadak since 2015. On 9 June 2019, Pius and Kadak married. The couple have a daughter, born on 25 March 2017, and a son, born 31 May 2020.[10] The family currently reside in Tallinn.

Both Märt and Priit Pius have been diagnosed with Diabetes mellitus type 1 and speak openly about living with the condition in order to raise awareness of the illness.