Giannis Kalatzis (Greek: Γιάννης Καλατζής, born 29 April 1943) is a Greek singer who was especially popular in Greece in the late 1960s and the early 1970s.

Giannis Kalatzis was born in Thessaloniki in 1943. His career as a singer began in the early 1960s when he was a member of the Trio Moreno in Thessaloniki. Kalatzis later moved to Athens, where he co-operated with the famous Greek composer Giorgos Mitsakis. His popularity began to increase and he had a productive collaboration with some of the most famous Greek composers of the period - Manos Loizos, Stavros Kougioumtzis, Giorgos Katsaros, Mimis Plessas, Giannis Spanos and released albums with Giorgos Dalaras, Haris Alexiou, Giannis Parios. He also appeared in 9 films.

In the second half of the 1970s Kalatzis's popularity started declining, as his albums met with less success. He gave up active singing in the 1980s but in 1985, he took part in a big concert dedicated to the memory of composer Manos Loizos that took place in Athens Olympic Stadium. The songs of Kalatzis are still popular in Greece and have been performed by other singers as well. He has released a couple of 'best of' albums.