Pontic Greek (Pontic: Ρωμαίικα, romanized: Rhomaiika, Greek: Ποντιακά, romanized: Pontiaka; Turkish: Rumca or Romeika), also referred to as Pontic, is a variety of Modern Greek indigenous to the Pontus region on the southern shores of the Black Sea, northeastern Anatolia, and the Eastern Turkish and Caucasus region. An endangered Greek language variety, Pontic Greek is spoken by about 778,000 people worldwide, who are known as Pontic or Pontian Greeks.

Like nearly all of Greek varieties spoken today, the linguistic lineage of Pontic Greek stems from the Hellenistic Koine, itself based on Attic–Ionic Greek, which later developed into the Byzantine Greek of the Middle Ages. Following its geographic isolation from the rest of the Greek–speaking world, Pontic continued to develop separately along with other Anatolian Greek dialects, like Cappadocian, from the 11th century onwards. As a result, Pontic Greek is not completely mutually intelligible with the standard Demotic Greek spoken in mainland Greece today. Pontic also contains influences from Russian, Turkish, Kartvelian (namely Laz and Georgian) and Armenian.

Today, Pontians live predominantly in Northern Greece, following the 1923 population exchange between Greece and Turkey. Out of their total population, around 200,000–300,000 are considered active Pontic speakers. Pontic Greek is also spoken in Turkey, Russia, Georgia, Armenia, and Kazakhstan, as well as by the Pontic diaspora. It remains spoken in pockets of the Pontus region, mostly by Pontic Greek Muslims in the eastern districts of Trabzon Province. Pontic is primarily written in the Greek script; the Latin script is sporadically used in Turkey, while the Cyrillic alphabet is rarely used in Russia and former Soviet countries.

Pontic Greek is classified as an Indo-European, Greek language of the Attic-Ionic branch.

Historically, the speakers of Pontic Greek referred to their language as Romeika, also spelled in Latin as Romeyka (Pontic: Ρωμαίικα); a historical and colloquial term also used for the Modern Greek language as a whole. Originating in Byzantine times, the term reflects the identification of the Greek–speaking Byzantine subjects as Rhomaioi (Ῥωμαῖοι) and the Medieval Greek language as Rhomaikḗ (Ῥωμαική). The term "Pontic" originated in scholarly usage, but it has been adopted as a mark of identity by Pontic Greeks living in Greece, where the language is commonly called Pontiaká (Greek: Ποντιακά). Pontians also refer to their language as Ποντιακόν λαλίαν Pontiakón lalían ('Pontic speech') and at times as Λαζικά Laziká.^{[citation needed]} The variety is also called Ποντιακή διάλεκτος Pontiakḗ diálektos ('Pontic dialect') in standard modern Greek.

In Turkish, there is no special name for Pontic Greek; it is called Rumca ([ˈɾumd͡ʒa]), derived from the Turkish word Rum, denoting Byzantine Greeks. Nowadays, Pontic speakers living in Turkey call their language Romeyka, Urumce, Rumca or Rumcika.

Similar to most modern Greek dialects, Pontic Greek is mainly derived from Koine Greek, which was spoken in the Hellenistic and Roman times between the 4th century BC and the 4th century AD. Following the Seljuk invasion of Asia Minor during the 11th century AD, Pontus became isolated from many of the regions of the Byzantine Empire. The Pontians remained somewhat isolated from the mainland Greeks, causing Pontic Greek to develop separately and distinctly from the rest of the mainland Greek. However, the dialect has also been influenced by the nearby Persian, Caucasian, and Turkish languages.

Greek linguist Manolis Triantafyllidis has divided the Pontic of Turkey into two groups: