Galatsi (Greek: Γαλάτσι, Galátsi [ɣaˈlatsi]), called in Katharevousa Galatsion (Greek: Γαλάτσιον, Galátsion), is a northern suburb of Athens, Greece, and a municipality of the Attica region. The municipality has an area of 4.026 km2.
Until the mid-20th century, the area was mainly made up of farmlands but due to the continuous expansion of the Greek capital, Galatsi was rapidly urbanised and has come to lie in the center of the Athens agglomeration.
It is one of the most densely populated areas of Athens, with a high percentage of its lands covered by flora though, as the hill of Tourkovounia with its forests and the park Alsos Veikou are among the major "green lungs" within the centre of Athens. The famous Grava school complex is located there, as are many other educational foundations and public and private institutes.