Sextus Afranius Burrus (died ad 62) was the praetorian prefect (51–62) and, with Seneca, the chief adviser of the Roman emperor Nero (reigned 54–68).
Burrus came from Vasio (now Vaison, France). After brief service in the army, he held posts in the households of Livia (the widow of the emperor Augustus) and the emperors Tiberius and Claudius; he probably worked in the household of Caligula as well. After Julia (also called Agrippina the Younger) married Claudius (49), she secured Burrus’s appointment as sole prefect of the Praetorian Guard (there were usually two prefects), whose loyalty he ensured when in 54 Nero succeeded to the throne at age 16. Burrus, in cooperation with Seneca, at first submitted to Agrippina but then removed her from power. Although unwilling to endorse her assassination by Nero in 59, Burrus again kept the Praetorian Guard loyal after her murder. Burrus and Seneca, who had been largely responsible for formulating Nero’s policies at the beginning of his reign, gradually lost influence. When Burrus died in 62, it was alleged that Nero had poisoned him, and Seneca was moved to resign immediately.