Eftichia Papagianopoulou (Greek: Ευτυχία Παπαγιαννοπούλου), also spelled as Eftihia Papagianopoulou (1893 – 7 January 1972), was a Greek lyricist.

She was born in Aydın near Smyrna (now İzmir) in Asia Minor in 1893. She left Smyrna in 1919 prior to the Greco-Turkish War. She emigrated to Greece and settled permanently in Athens.

She wrote the lyrics to many popular Greek songs, co-operating with composers like Vassilis Tsitsanis, Apostolos Kaldaras and Manos Hadjidakis; however, she never became very famous among the public until her 1972 death. Her great contribution to Greek music through her exceptional ability in writing lyrics wasn't broadly known and recognized, although many of the successful songs of the 1950s and 1960s had been composed by her.

A recent (2002) book written by lyricist and journalist Lefteris Papadopoulos, who was a friend of Eftichia during the last years of her life, helped a lot to increase recognition for her work.

Her life was recorded in a book written by her granddaughter, Rhea Manelli, titled "My Grandmother's Happiness". This biography inspired the theatrical monologue performed by Nena Menti in the show bearing her name as the title.

In 2019, her life was made into a movie titled after her and starring Katia Goulioni (young age) and Karyofyllia Karabeti (older age) in the title role.