Attalus or Attalos may refer to:

• Several members of the Attalid dynasty of Pergamon
  • Attalus I, ruled 241 BC–197 BC
  • Attalus II Philadelphus, ruled 160 BC–138 BC
  • Attalus III, ruled 138 BC–133 BC
• Attalus, father of Philetaerus the founder of the Attalid dynasty of Pergamon
• Attalus, father of Attalus I of Pergamon
• Attalus (general) (390–336 BC), courtier and general of Philip II of Macedonia
• Attalus (son of Andromenes) (fl. 330–317 BC), general of Alexander the Great and Perdiccas
• Attalus of Rhodes (fl. 2nd century BC), astronomer, contemporary of Hipparchus
• Attalus (Stoic) (fl. 25 AD), Stoic philosopher and teacher of Seneca
• Attalus (sophist), (fl. 2nd century) sophist, son of Polemon of Laodicea
• Statilius Attalus (fl. 2nd century), court physician of the emperor Marcus Aurelius
• Priscus Attalus (fl. 409–416), Roman senator who was proclaimed emperor twice by the Visigoths
• St Attalus, Sicilian saint and protomartyr, bishop of Catania
• Attalus (Marcomanni) [cs], King of Marcomanni
• Attalus (mythology) (also called Perdix or Talos), mythical nephew of Daedalus credited as the inventor of the potter's wheel, saw, and drawing compass
• Attalus (sculptor), statuary of ancient Greece whose time is unknown

• Attalus, a genus of beetles in the family Melyridae
• Alburnus attalus, a ray-finned fish of family Cyprinidae
• Henricus attalus, a moth of family Tortricidae

• Attalus (band), an American rock band formed in 2010
• Attalus (UAV), a Greek anti-tank loitering munition