Lembit Ulfsak (July 4, 1947 in Koeru – March 22, 2017) was an Estonian actor and director.

Ulfsak spent his childhood in Räpina, where he also finished the 8th grade. In 1966, he graduated from Tallinn 7th Secondary School. From 1966 to 1970, he studied at the Tallinn State Conservatory's Department of Performing Arts (4th class).

Ulfsak worked mainly at the Estonian SSR State Youth Theatre and Drama Theatre, as well as at Tallinnfilm. In addition to his theatre work, he acted in many films, the most internationally known of which are the leading roles in the films "The Legend of Till" (1976) and the Georgian-Estonian collaboration film "Tangerines" (2013), which was among the five best foreign language films in 2014 before the Oscar and Golden Globe awards.

From 1972 to 1973, he sang in the Band Amor Trio.

On June 1, 2019, a memorial bench installed in Ulfsak's honor was unveiled near his coastal home on the western shore of the Kakumäe Peninsula.