Athanasios (Greek: Αθανάσιος), also transliterated as Athnasious, Athanase or Atanacio, is a Greek male name which means "immortal".^[1] In modern Greek everyday use, it is commonly shortened to Thanasis (Θανάσης), Thanos (Θάνος), Sakis (Σάκης), Nasos (Νάσος), Athan (Αθαν) or Athos (Aθως).

The female version of the name is Athanasia [el] (Greek: Αθανασία), shortened to Sia (Σία) or Nancy (Νάνσυ)

Notable people with this name include:

• Athanasius of Alexandria (ca. 296/298–373), Christian saint, Coptic pope, theologian
• Pope Athanasius II of Alexandria (died 496), Coptic pope from 490 to 496
• Athanasius I Gammolo (died 631), Patriarch of Antioch, and head of the Syriac Orthodox Church of Antioch from 595 until his death
• Athanasius II Baldoyo (died 686), Patriarch of Antioch, and head of the Syriac Orthodox Church from 683 until his death
• Athanasius Sandalaya, Patriarch of Antioch, and head of the Syriac Orthodox Church from 756 until 758
• Athanasius I (bishop of Naples) (died 872), Italian bishop
• Athanasius of Naples (died 898), bishop and Duke of Naples
• Athanasius IV of Salh (died 1002), Patriarch of Antioch, and head of the Syriac Orthodox Church from 986 until his death
• Athanasius the Athonite (c. 920–c. 1003), Byzantine monk and saint who founded the monastic community on Mount Athos
• Athanasius VI bar Khamoro (died 1129), Patriarch of Antioch, and head of the Syriac Orthodox Church from 1091 until his death
• Pope Athanasius III of Alexandria, Coptic pope from 1250 to 1261
• Athanasius I of Constantinople (1230–1310), Greek Patriarch of Constantinople, Eastern Orthodox saint
• Patriarch Athanasius III of Alexandria, Greek Patriarch of Alexandria between 1276 and 1316
• Athanasius the Meteorite (1302–1380), Greek monk who founded the Monastery of Great Meteoron in Meteora, Greece
• Patriarch Athanasius IV of Alexandria, Greek Patriarch of Alexandria between 1417 and 1425
• Athanasius II of Constantinople, last Greek Patriarch (1450–1453) of an independent Constantinople
• Athanasius, Metropolitan of Moscow (died in the 1570s), Metropolitan of Moscow and all Russia from 1566 to 1568, writer and icon painter
• Athanasius II Dabbas (died 1619), Greek Patriarch of Antioch from 1611 to his death
• Athanasius of Brest (died 1648), Lithuanian martyr of the Orthodox Church
• Athanasius III of Constantinople (1597–1654), Patriarch of Constantinople in 1634, 1635 and 1652
• Athanasius III Dabbas (1647–1724), Greek Patriarch of Antioch and Archbishop of Cyprus
• Athanasius IV of Constantinople, Ecumenical Patriarch of Constantinople in 1679
• Athanasius of Attalia (died 1700), Orthodox martyr of Smyrna
• Athanasius V of Constantinople, Greek Patriarch of Constantinople from 1709 to 1711
• Athanasios Parios (1722–1813), Greek hieromonk, theologian, philosopher, educator and hymnographer
• Athanasius V Matar, Patriarch of the Melkite Greek Catholic Church for a few months in 1813
• Athanasius Schneider (born 1961), Roman Catholic bishop
• Athanasiy Velyki (1918–1982), Ukrainian Basilian priest, historian, member of the Shevchenko Scientific Society

• Athanasios Angelopoulos (born 1939), Greek professor of theology
• Athanasios Asimakopulos (1930–1990), Canadian economist
• Athanasios Kafkalides (1919–1989), Greek neuropsychiatrist
• Athanasius Kircher (1602–1680), German Jesuit scholar and polymath
• Athanasios Moulakis (1945–2015), Greek Professor of Government
• Athanasios Rousopoulos (1823–1898), professor
• Athanasios Psalidas (1767–1829), author, scholar and one of the most renowned figures of the modern Greek Enlightenment
• Athanasios Stageiritis (fl. 19th century), professor of Greek language at the Imperial Academy in Vienna
• Athanasios Tsakalidis (born 1950), Greek computer scientist
• Athanasios Pantelous (born 1978), Greek associate professor in actuarial science and financial mathematics
• Athanasius Abram (born 1990), Senior Client Coordinator

• Athanasios Diakos (1788–1821), Greek military commander during the Greek War of Independence
• Athanasios Dimitrakopoulos (1936–2022), Greek politician
• Athanasios Eftaxias (1849–1931), former Prime Minister of Greece
• Athanasios Exadaktylos (1869–1936), Greek Army general
• Athanasios Frangou (1864–1923), Greek Army officer
• Athanasios Kanakaris (1760–1824), Greek revolutionary and politician
• Athanasios Kanakaris-Roufos (1830–1902), politician, mayor of the city of Patras
• Athanasios Kanellopoulos (1923–1994), Greek politician, Deputy Prime Minister of Greece (1990–1992)
• Athanasios Klaras (1905–1945), military leader of ELAS (nom de guerre Aris Velouchiotis)
• Athanasios Miaoulis (1815–1867), former Prime Minister of Greece
• Athanasios N. Miaoulis (1865–1936), former Mayor of Piraeustu
• Thanos Mikroutsikos (1947–2019), Greek songwriter and politician
• Atanas Paparizov (born 1951), Bulgarian politician and Member of the European Parliament
• Athanasios Pipis (died 1821), revolutionary in the Greek War of Independence
• Thanos Plevris (born 1977), Greek politician
• Athanasios Roussopoulos (1903–1983), Greek politician
• Athanasios Tsakalov (died 1851), Greek revolutionary against Ottoman rule, co-founder of the Filiki Eteria secret revolutionary organization
• Athanasios Tsaldaris (1921–1997), Greek politician, Speaker of the Hellenic Parliament at various times from 1989–1993

• Athanasios Christopoulos (1772–1847), Greek poet
• Thanos Kalliris (born 1962), Greek pop singer
• Thanos Mikroutsikos (born 1947–2020), Greek songwriter and politician
• Panas Myrny (1849–1920), Ukrainian prose writer and playwright
• Thanos Petrelis (born 1975), Greek pop singer
• Sakis Tolis (born 1972), Greek musician best known as the vocalist and rhythm guitarist of Rotting Christ
• Sakis Rouvas (born 1972), Greek singer

• Athanasios Kostoulas (born 1976), Greek footballer
• Athanasios Mantzouranis (born 1982), Greek cyclist
• Athanasios Michalopoulos (born 1973), Greek beach volleyball player
• Athanasios Nanopoulos, Greek fencer
• Athanasios Skaltsogiannis (born 1878, date of death unknown), Greek hurdler and long jumper
• Athanasios Skourtopoulos (born 1965), Greek basketball player
• Athanasios Stoikos (born 1988), Greek footballer
• Athanasios Tsigas (born 1982), Greek footballer
• Athanasios Vouros, Greek fencer
• Thanasis Antetokounmpo (born 1992), Greek basketball player
• Thanasi Kokkinakis, Australian tennis player
• Athanasios Protopsaltis, (born 1993, Limassol Cyprus), Greek volleyball player

• Athanasios of Emesa, 6th-century Byzantine jurist
• Athanasius (praetorian prefect), 6th-century Byzantine official
• Afanasy Nikitin, Russian merchant, one of the first Europeans to travel to and document his visit to India. Died 1472.
• Athanasios Lefkaditis (1872–1944), founder of Greek Scouting
• Athanasios Papoulis (1921–2002), Greek-American engineer
• Athanasios Polychronopoulos (born 1984), Greek-American professional poker player

• Thanasis, a given name
• Thanos (name), a given name and a surname
• Afanasy, the Russian form of Athanasios
• Athanase, a given name
• Atanasio, a given name