Quintus Poppaedius Silo (sometimes seen as Pompaedius) was the leader of the Italian tribe of the Marsi and one of the leaders of the Italians during the Social War against Rome. He was a friend of Marcus Livius Drusus the Younger.
A story told by Plutarch tells of Silo, who made a visit to his friend Marcus Livius and met the children of the house. In a playful mood he asked the children's support for his cause. All of them nodded and smiled except Cato the Younger, who stared at the guest with most suspicious looks. Silo demanded an answer from him and seeing no response took Cato and hung him by the feet out of the window. Even then, Cato would not say anything.
After Drusus's murder, the Social War started and Silo became the military leader of the Marsii. He was killed in battle by Drusus's brother Mamercus Aemilius Lepidus Livianus.