The Scourge of the Underworld is the name of a series of fictional characters who have appeared in various series set in the Marvel Comics universe. The Scourge would appear, usually in disguise, execute a minor supervillain, shout "Justice is served!", and disappear.

The Scourge first appeared in Iron Man #194 (1986) and made single-issue appearances in most of Marvel's series published at the time, although the bulk of his story was told in Captain America #318-320. The Scourge of the Underworld first surfaced as a taxicab driver who unexpectedly executed a villain leaving the scene of a crime, and most of the Scourge's other assassinations were committed under similar disguises. His most infamous appearance was in Captain America #319, in which he killed over a dozen minor supervillains at the "Bar With No Name". According to the Scourge in Captain America #320, he was the brother of the Enforcer, a minor villain who had been one of his first victims. The Scourge making this confession was then executed by another Scourge, and that Scourge was later killed by yet another Scourge. This last Scourge also killed the Soviet agent who had used the identity of the Red Skull in the 1950s. It was revealed in Captain America #350 that the Scourge had been financed by the original Red Skull, who had been believed dead at the time but had actually survived in a body that was cloned from Captain America's DNA.

Years later, in the USAgent miniseries, it was revealed that the Scourge was an identity used by several people, all of whom were financed by the original Angel, a hero from the Golden Age of Comic Books who had been driven to vigilantism in recent years. USAgent and the Vagabond fought the Scourges, including one who had claimed to be the USAgent's brother. In the end, the Angel died (although he was survived by a brother who had also used the identity of the Angel) and the remaining Scourges were defeated and arrested.

In the pages of Thunderbolts, a new Scourge appeared; this one assassinated the Thunderbolts members Jolt, Baron Zemo and Techno, as well as several civilians. It was revealed that this Scourge was actually Jack Monroe, alias Bucky and Nomad , who was being mentally controlled by the superhuman-hating government agent Henry Peter Gyrich; Gyrich himself was being manipulated by Baron Strucker. Munroe was being defeated and freed from Gyrich's control by the Thunderbolts and their allies, the Redeemers, and apparently abandoned the Scourge equipment and identity after the battle.