The characters featured in the 2012 Nickelodeon-produced Teenage Mutant Ninja Turtles series. For tropes relating to versions of characters from other incarnations of the franchise, please visit the franchise character page.
- The Hamato Clannote Hamato Leonardo, Hamato Donatello, Hamato Raphael, Hamato Michelangelo, Splinter/Hamato Yoshi, April O' Neil, Casey Jones, Spike, Ice-Cream Kitty, Chompy Picasso
- Allies and Civiliansnote Inhabitants of New York (Kirby O' Neil, Metalhead, Murakami, Timothy/The Pulverizer/ Mutagen Man, Joan Grody, Irma, Sir Malachi, Jack J. Kurtzman), The Mighty Mutanimals (Slash, Leatherhead, Pigeon Pete, Dr. Tyler Rockwell, Garson Grunge/Muckman, Mondo Gecko, Mona Lisa), The Utroms (Agent Bishop, Queen, Pawn, Rook), Earth Protection Force (General Griffin), Alternate Feudal Japan (Miyamoto Usagi, Kintaro), Other Characters (Punk Frogs, Bigfoot, Dr. Cluckingsworth M.D., Renet, Lord Simultaneous, Tang Shen, Sal Commander, Professor Zayton Honeycutt, '87 Turtles, Tokka, Alopex)
- The Foot Clannote Rogue Foot (Hamato Miwa/Oroku Karai, Shinigami), Purple Dragons (Hun, Fong, Tsoi, and Sid), Foot Soldiers and Other Associates (Koga Takuza, The Foot Ninjas, Shredder mutants/Mega-Shredder, Chrome Dome, The Foot Cultists, Hattori Tatsu), The Vizioso Mafia (Don Vizioso, The Fulci Twins, The Hammer)
- The Shredder's Inner Circlenote Oroku Saki/The Shredder/Super Shredder, Chris Bradford/Dogpound/Rahzar, Xever Montes/Fishface, Baxter Stockman/Stockman-Pod/Stockman-Fly, Takeshi/Tiger Claw, Ivan Steranko/Rocksteady, Anton Zeck/Bebop, Kavaxas
- The Kraangnote Kraang Prime, Mrs. Campbell, Traag, Granitor, The Sea Monster, Kraang Sub-Prime, Krang
- Other Villainsnote Major Recurring Villains (Dr. Victor Falco/The Rat King, The Newtralizer/K'Vathrak, Ivan Steranko, Anton Zeck, Savanti Romero, Vringath Dregg, Armaggon,Zog, Captain Mozar, General Zera, Zeno, Emperor Zanmoran, Jei), Minor recurring/One-off villains (Snake/Snakeweed, Vic/Spider Bytez, Justin, Spy-Roach, The Parasitic Wasp, Squirrelanoids, Pizza Face, Ho Chan, The Creep, The Finger, Dream Beavers, Speed Demon, Wyrm, Overmind, Za-Naron, Sumo Kuma, Jei, The Mummy, Count Dracula, '87 Shredder)
- TV Show Charactersnote Captain Ryan, Crankshaw, Dr. Mindstrong, Rodriguez, That Other Guy, Celestial, Hypnotica, Panicons, Trumplets, Cortexicons, Captain Dash Coolstar, Dr. Blip, Lunk, Squeakums, Princess, The Mighty Super Robo Mecha, Kill Beast Bots, Giant Space Squid, Cyberoid X, General Unsura, Mind Master, Hydra Beast, Skele-Lord, Crognard, Wizardess, Spooch, Graah, Slug People, Golek, Giant Mountain Demon, Muurg, Megalord Zarrik, Grom and Grum, Gorrick Army, Malfidor, Rock Giant, Dread Dragon Wigglepuss, Chris Bradford, Lil' Rineo, Master C, Sumo Glen, Cho-Cho, Fake Master, Evil Ninja, Micro Chip, Captain Reptile, Destroyo, Ninja Commander, Giant Yellow Monster, Captain Ryan (Older), Crankshaw Jr., The Nefrini, Z, Shahana, Scronus, Dr. Mindstrong (Older), The Cybergs, Mr. Gigabyte, Lt. LeTrois
