Arcadian may refer to:

• Arcadian, someone or something from, or related to:
  • Arcadia (region), the ancient Greek region
  • Arcadia (regional unit), the region in modern Greece
  • Accademia degli Arcadi, the Italian literary academy founded in Rome
  • any of the other places known as "Arcadia"
• Arcadian Greek, the dialect spoken in ancient Arcadia
• Arcadian ecology, an environmentalist perspective
• Bebearia arcadius, a butterfly in the family Nymphalidae

• Arcadian (Star Trek), a race in Star Trek
• The Arcadian, a 2011 American science fiction film
• Arcadian (film), a 2024 American post-apocalyptic horror film starring Nicolas Cage
• Arcadian (band), a Franco-Swiss band

• SS Arcadian, formerly the 1899 ship, SS Ortona, she was torpedoed and sunk in 1917
• RMSP Asturias (1907), renamed RMSP Arcadian in 1923 and scrapped in 1933
• HMS Arcadian, a projected Amphion-class submarine, the order for which was cancelled in 1945

• Arcadia (disambiguation)
• Arcadians (disambiguation)
• Acadian, Cajun