Niki Triantafyllidi (Athens, November 27, 1942 - Athens, May 13, 2013) was a Greek actress, director and writer. She was the daughter of composer Panos Triantafyllidis. She graduated from the Drama School of the National Theatre.

She made her theatrical debut in 1963, in the play "The House of Bernarda Alba" by Federico García Lorca with the Aleka Katseli troupe. She acted in several Greek films. She collaborated with important directors such as Alexis Minotis, Minos Volanakis, Lefteris Charonitis and others. In 1969 she was for a short time artistic director of the theater organization "Christian Theater", where she staged Eugene O'Neill's play, "Endless Days". In 1970 she won the directing award at the Thessaloniki Film Festival, for the short film "My Ordinary Dream", while in 1971 she was honored by the "Center for Study and Research of the Greek Theater" with the "Marika Kotopouli" award as the best actress of the period 1970-71. She taught at the State Theater of Northern Greece, at the Pelos Katselis school and at the Mary Traga school. He was a founding member of the Ensemble Theater and the Panhellenic Cultural Movement and in the 1990s he founded the "Triantafyllidis" Theater in Vathis Square.