Attalos (Latin Attalus ) is a Greek male first name and the name of the following historical persons:
- Attalus (general) († 336 BC), Macedonian general
- Attalus I Soter (269 BC - 197 BC), King of Pergamon.
- Attalus II Philadelphos (220 BC - 138 BC), King of Pergamon.
- Attalus III. Philometor (171 BC - 133 BC), King of Pergamon.
- Attalus (Diadoche) († 316 BC), bodyguard of Philip II of Macedonia and brother-in-law of Perdiccas
- Attalos of Rhodes (around 200 BC), mathematician and astronomer
- Attalus (4th century BC), ancestor of the Attalids
- Priscus Attalus († after 416), Western Roman counter-emperor