Athanasios "Thanasis" Papakonstantinou (Greek: Αθανάσιος (Θανάσης) Παπακωνσταντίνου; born 26 April 1959) is a Greek singer-songwriter.

He is married, with two children. Papakonstantinou studied mechanical engineering in Thessaloniki, which he practices as well as being a musician. After military service (all males are conscripted in Greece), he had a spell of handcrafting traditional Greek musical instruments.

Now a Larissa resident, Papakonstantinou has established himself as one of the most original and prolific people in the Greek music scene. He writes music in the Greek folk idiom, stemming from his own recollections of traditional songs his parents sang while working in the field. He usually writes his own lyrics or uses poems. He has collaborated with numerous notable artists from the Greek music scene, such as Giannis Aggelakas, Melina Kana, Sokratis Malamas, Lizeta Kalimeri, Nikos Papazoglou.

In 2002, his song Nanourisma was featured in the film by Nikos Grammatikos O Vasilias (The King). The 2007 documentary The Horns of the Bull is dedicated to Papakonstantinou's work.