| Villain | First appearance | Description |
| Black Mace | Adventure Comics #374 | A highly trained and super-strong mercenary. |
| Blight | Legion of Super-Heroes: Secret Files and Origins #2 | An alien race of cybernetic zombies. The Blight travel through space, infesting races they come in contact with. |
| Chameleon Chief | Superman's Pal, Jimmy Olsen #63 | A Durlan and member of the Legion of Super-Villains who can transform himself and other objects. |
| Command Kid | Adventure Comics #328 | A resident of Preztor who is possessed by a demon. He infiltrates the Legion of Super-Heroes to destroy them, but is foiled by his weakness to gold. |
| Composite Man | Legionnaires #25 | A bio-engineered Durlan mutant who mimics the powers of the Legion of Super-Heroes when they arrive to stop his murderous rampage for Legionnaire Chameleon. |
| Computo | Adventure Comics #340 | A mechanical assistant built by Brainiac 5. Computo sought to wipe out humanity in favor of the rule of machines, proving to be one of the Legion of Super-Heroes' most frequent opponents. |
| Controller | Adventure Comics #357 | The Controllers are an alien species from another dimension. One Controller, believing true perfection to be derived from chaos, creates a Sun-Eater to attack the universe before the Legion stops him. |
| Cosmic King | Superman #147 | A resident of Venus who created a matter-manipulating beam and developed its abilities innately. Shunned by the government, he becomes Cosmic King and a founding member of the Legion of Super-Villains. |
| Dark Circle | Adventure Comics #367 | A criminal organization founded by five members and consisting of them and their clones. In post-Zero Hour continuity, the group is depicted as a religious movement. |
| Darkseid | Superman's Pal Jimmy Olsen #134 | The dictator of Apokolips and an old enemy of Superman and the Justice League. After being resurrected in the 30th century, Darkseid battles the Legion. They defeat him, but he kidnaps Lightning Lad and Saturn Girl's son Garridan and transforms him into Validus as revenge. |
| Doctor Regulus | Adventure Comics #348 | Regulus is a scientist at a nuclear power plant in Metropolis whose experiments were interrupted by Dirk Morgna. Regulus throws Dirk into a nuclear reactor out of anger, which unintentionally gives him solar abilities. Regulus goes into hiding and builds powered armor to seek revenge on Dirk. |
| Dominators | Adventure Comics #361 | An alien race of scientists ofttimes at odds with Earth. They participated in Earthwar and were part of an alliance against Earth. |
| Dynamo Boy | Adventure Comics #330 | A space pirate from New Tortuga, Vorm uses a special belt to infiltrate the Legion of Super-Heroes to destroy them from within for the threat they pose to his species's trade. Through circumstances, he managed to expel all members save himself and built a new Legion with three members of the Legion of Super-Villains. |
| Echo | Adventure Comics #355 | A metahuman with the ability to manipulate sound waves. |
| Esper Lass | Superboy Starring the Legion of Super-Heroes #212 | A Titanian with telepathic powers who was denied membership into the Legion for possessing the same powers as Saturn Girl. Subsequently, she becomes a founding member of the Legion of Super-Rejects. |
| Evillo | Adventure Comics #350 | Prince of the planet Tartarus, Evillo lures criminals to his world with safe haven and siphons their evil to turn innocent people into villains. Creating a group of criminals called the "Devil's Dozen", his gang robbed other planets for him. |
| Fatal Five | Adventure Comics #352 | A group of five of the greatest criminals in the universe: Emerald Empress, Mano, the Persuader, Tharok, and Validus. They initially meet while helping the Legion battle the Sun-Eater, and decide to remain together afterward. |
| Firefist | Legion of Super-Heroes #44 | A Khund who is forced to work with the Legion of Super-Heroes and later betrays them. He is a cyborg and possesses superhuman physical abilities. |
| Glorith | Adventure Comics #338 | In pre-Crisis continuity, Glorith is an agent of the Time Trapper who he killed for her failure to defeat the Legion of Super-Heroes. Post-Crisis, Glorith becomes a frequent and dangerous enemy of the Legion using her ability to manipulate time. |
| Grimbor the Chainsman | Superboy #221 | An inventor and expert in confinement devices, Grimbor is entranced by the mutant Charma Drisden into becoming a criminal after being tasked with capturing her. |
| Hunter | Adventure Comics #358 | Otto Orion was a master hunter on the planet Simballi who became its ruler. Orion sought to hunt the Legion of Super-Heroes only to meet his demise. His son Adam sought revenge on the Legion, first alone and later as part of the Legion of Super-Villains. |
| Infinite Man | Superboy and the Legion of Super-Heroes #233 | Professor Jaxon Rugarth volunteers for a device invented by Rond Vidar intended to send someone forward enough in time to enter the past and prove the theory that the fourth dimension is circular. Rugarth, however, is sent through several dimensions and across time, breaking his mind and turning him into the powerful creature Infinite Man. |
| Justice League of Earth | Action Comics #859 | Spurned by being rejected for membership into the Legion of Super-Heroes, a group of people led by Earth-Man push the people of Earth into becoming a xenophobic society believing its greatest hero, Superman, was in fact from Earth and protected the world from alien influence. Becoming the Justice League of Earth, the group made the Legion of Super-Heroes into outcasts and hunted by authorities. |
| Khund | Adventure Comics #346 | A vast empire of warriors and cyborg conquerors. |
| Laurel Kent | Superboy #217 | Lauren Kent is a student of the Legion Academy who is believed to be a descendant of Superman. She is later revealed to be a Manhunter and self-destructs after her programming activates. |
| League of Super-Assassins | Superboy and the Legion of Super-Heroes #253 | Believing their planet Dryad was destroyed by the Legion of Super-Heroes, the actual culprit Dark Man subjected the youths to experiments to give them powers to battle the Legion. Member Blok ended up joining the Legion and his teammates were folded into the Legion of Super-Villains. |
| Legion of Stupor-Bizarros | Adventure Comics #329 | A group of Bizarro clones of the Legionnaires created by Bizarro's descendant. |
| Legion of Super-Rejects | Superboy #212 | A group of youths who were rejected from the Legion for having duplicate powers. |
| Legion of Super-Villains | Superman #147 | First appearing as an adult villainous counterpart of the Legion of Super-Heroes, the group is summoned to the past by Lex Luthor to destroy Superman. The group was later revealed to initially be members of the School of Super-Villains that grew to eventually include most of the Legion's enemies. |
| Leland McCauley | Adventure Comics #374 | An industrialist and rival of R. J. Brande. |
| Lex Luthor | Action Comics #23 | Superboy's close friend who became his gravest enemy; when Luthor learned of the Legion of Super-Heroes the group contracted his ire as well, with him facing the group as a teenager and adult. |
| Lightning Lord | Superman #147 | The elder brother of Lightning Lad and Light Lass who gained electric superpowers alongside them after being attacked by Lightning Beasts. After being shunned throughout his life for being an only child, Mekt becomes a criminal and founding member of the Legion of Super-Villains. |
| Luck Lords | Adventure Comics #343 | The name of two groups. The first is a quartet of alien criminals who were exiled from their world and wield mind-controlling technology. The second is a group of immortal mages. |
| Mordru | Adventure Comics #369 | Appearing mysteriously on Zerox, Mordru joined their society before seizing power and absorb the power of many of their wizards. He began conquering neighboring worlds, forming an extensive empire that spans half a galaxy. Deciding to begin being more selective with what worlds he would snatch up, Earth would catch his eye and he would battle the Legion of Super-Heroes, becoming one of the group's most frequent adversaries. |
| Nemesis Kid | Adventure Comics #346 | An undercover agent of the Khunds with the ability to develop whatever power is necessary to defeat his opponent. |
| Omega | Superboy and the Legion of Super-Heroes #250 | Created by a mad Brainiac 5 to destroy the universe, the Miracle Machine took the combined hatred of the universe and gave it form in Omega. |
| Pulsar Stargrave | Superboy #223 | A Coluan who claims to be Brainiac resurrected and imbued with stellar energy. |
| Ra's al Ghul | Batman #232 | An old enemy of Batman who possesses immortality derived from the Lazarus Pits. In the 31st century, he kills United Planets president Leland McCauley and takes his place, ordering that the Legion of Super-Heroes were outlaws. By this time, Ra's had become one with the Lazarus Pits' fire and could inhabit one of many clones made of himself. |
| Roxxas | Adventure Comics #307 | A space pirate who massacred the Trommites when they refused to use their ability to transmute elements to avast a fortune. The sole survivor, Jan Arrah, joins the Legion of Super-Heroes as Element Lad. |
| Saturn Queen | Superman #147 | A Titanian and founding member of the Legion of Super-Villains. |
| School for Super-Villains | Adventure Comics #371 | A school for supervillains founded by Tarik the Mute. |
| Sklarian Raiders | Superboy and the Legion of Super-Heroes #233 | An all-female band of space pirates. |
| Spider Girl | Adventure Comics #310 | A rejected Legionnaire applicant and member of the Legion of Super-Villains who possesses prehensile hair. |
| Starfinger | Adventure Comics #335 | Originally, Starfinger is an alternate identity of Lightning Lad, who was mind-controlled by Lars Hanscom. Later, criminal Char Burrane and Lars' brother Molock Hanscom obtain a set of alien rings and take on the Starfinger mantle. |
| Storm Boy | Adventure Comics #301 | A member of the Legion of Super-Villains who was rejected from the Legion of Super-Heroes after they discovered that his weather-manipulating abilities are derived from a hidden device and are not natural. |
| Sun Emperor | Superboy #208 | A criminal and member of the Legion of Super-Villains who gained the ability to manipulate solar energy after participating in a genetic experiment. |
| Superboy-Prime | DC Comics Presents #87 | An alternate universe variant of Superman. He battles the Legion after being sent to the 31st century by the Time Trapper, who is later revealed to be his future self. |
| Tarik the Mute | Adventure Comics #372
| During a fire fight between criminals and the Science Police, an innocent bystander named Tarik was struck by one of the officers' laser blasts. Rendered mute, Tarik came to despise the law and formed a school to train criminals so far to force Colossal Boy to become an instructor under threat of murdering his parents. Tarik's students would go on to found the Legion of Super-Villains. |
| Time Trapper | Adventure Comics #317 | A powerful, time-manipulating entity who resides at the end of time. Because of his ever-changing nature, he has had several identities, including his assistant Glorith, a Controller, Cosmic Boy, the young girl Lori Morning, and Superboy-Prime. |
| Tyr | Superboy #197 | An alien from the planet Tyrraz and a member of the Legion of Super-Villains. He wields a bionic gun in place of his right arm. |
| Universo | Adventure Comics #349 | A former Green Lantern who was stripped of his power ring after attempting to view the beginning of the universe. |
| Vandal Savage | Green Lantern #10 | A Cro-Magnon who gained immortality after being exposed to a radioactive meteor. He has battled various heroes, including the Legion of Super-Heroes. |
| White Triangle | Legion of Super-Heroes #66 | A xenophobic group of Daxamites who view other races as inferior and plot to destroy the United Planets due to its goal of uniting different races. |
| Workforce | Legion of Super-Heroes #64 | A group of superpowered youths formed by Leland McCauley to rival his enemy R. J. Brande's Legion of Super-Heroes. The Workforce members later abandon McCauley to become real heroes. |