- Ambassador Korobon: Appears in volume 4.
- Brother Ildak: Leader of the Illuminated Utrom Alliance, appears in Attack of the Replicants.
- Bydex: An Utrom appearing in in the issue Soul Survivor.
- Emissary Rikby: The Utrom driving the TCRI truck which carried the ooze that mutated the turtles and Splinter. Wishing to see his “children”, whom he felt responsible for, he recruited the turtles to save Leatherhead, who had been kidnapped by The Illuminated. In order to save the mutants, he implanted a bomb into himself, which he used to destroy the Illuminated’s base.
- Dr. Klynor: Appears in volume 4.
- Dr. Xeinos: A female Utrom scientist which first appeared in the non-canon (by Mirage standards) Volume 3 of the series. She was left behind on Earth after the Utroms left to their homeplanet, and found and befriended Leatherhead who nursed him back to health. She also played chess with Splinter. Dr. X later began making appearances in Tales of the TMNT vol. 2, where she is often seeing accompanying Leatherhead. In the short story Threads, she was revealed to be the one who found Leatherhead in the sewer when he was still a normal alligator.
- Captain Glonar Appears in Volume 4.
- Korobon: Korobon is an Utrom who declared himself ambassador to Earth from the Utrom Confederation. He addressed the U.N. on live television and explained what the Utroms had planned to do on Earth. He appeared in Volume 4 of the comic.
- Kuroda: Appears in Attack of the Replicants.
- Glurin: Glurin is a young Utrom scientist who was stationed on their Earth base. When April O'Neil was infected by nanobots placed in her body by Dr. Baxter Stockman, he came up with the idea of using other nanobots to combat them. He designed the new nanobots after the Turtles and called them the nanoturtlebots. He appeared in Volume 4 of the comic and Tales of the TMNT Volume 2.
- Glyminal: Member of a seven-member Utrom group that attempted incorporation of a charge in mutagen stranded in an inaccessible part of the South American jungle and had adapted to their new living conditions there.
- Navigator Thurak: Appears in Volume 4, gets eaten by a raptor.
- Sister Grum: Member of the Illuminated Utrom Alliance, appears in Attack of the Replicants.
- Professor Obligado: Obligado was a brilliant Utrom scientist whose life and death is shown in the back pages of the new Tales of the TMNT vol. 2.
- Dr. Oolric: Appears in the comic "Mere Appendix".
- Klag: Klag is an Utrom who helped Michelangelo in Michelangelo: The Third Kind mini-series. During the first contact with the Utroms he helps the prevent the escalation of violence within xenophobic hate groups through fighting them alongside Michelangelo and eventually using Utrom technology to kidnap and impersonate their leader and deliver an anti-hate speech.
- Nemoiku: A member of the Utrom Preservi.
- Rogro: Appears in the comic "The Curious Case of Mr. Jones"
- Sargeant Xitor: An Utrom who serves as a police officer on Earth, under the guise of a female human. In her appearances, she unsuccessfully tries to prevent the Utrom Preservi from taking the late Professor Obligado's memories.
- Security Officer Yat: An Utrom from the story Terror by Transmat!.
- Science Advisor Shuthan: Appears in Volume 4.
- Radical Utroms
- Utrom Preservi: A group of Utroms that specializes in the preservation of memories that are downloaded and archived directly from the brains of dead Utroms.
- Utromi Secreti Obscura:A kind of secret troop of Utroms, which is mainly used for concealment and monitoring tasks, particularly in the area of teleporter technology.
- The Enlightened Ones (The Illuminated): A group of Utrom fanatics that used a clone army (with Leatherhead (Mirage) as their source of DNA) in an attempt to wipe out all violent species in the galaxy.
- Mortu: Mortu was the captain of the Utrom ship that crashed on Earth. After the crash, he remained the field-leader of the marooned Utroms, and worked as their liaison to the Humans. In the modern day, this makes him CEO of the front company TCRI. His name is "Utrom" backwards.
- Council of Three: These three otherwise unnamed Utroms are the highest leaders of the Utroms on Earth. Although it is not explicitly stated, it is strongly implied that these are the same brain-navigators that Captain Mortu took orders from one thousand years ago aboard their ill-fated star ship.
- Ch’rell: The most ruthless criminal the universe has known. Ch'rell dreams of galactic domination, and wants vengeance against the Utroms for imprisoning him and denying him his dreams by building an army and attacking their homeworld. This is the true identity of The Utrom Shredder in the 2003 TV series. Prior to his arrival on Earth, he was responsible for the deaths of millions of people in his attempts at universal domination.
- Krang: A Utrom by the same name as the villain from the 1987 cartoon makes a brief cameo appearance in the episode Secret Origins, Part 2. He mentions how he hates walking on his tentacles.
- Abraham Lincoln: The 16th president of the United States is seen to secretly be an Utrom in an interstitial.
- Utrom High Council: The Utrom High Council is a collective body on the Utrom homeworld who appear to be the governing body of the planet and the navigators on the stranded ship. The judgements of Utrom criminals such as Ch'rell are carried out on the Utrom homeworld by the Utrom High Council. Not much is known, but they are responsible for the Utrom Shredder's banishment to a frozen asteroid.
- Utrominators: The Utrominator exo-suit is what was given to the Utroms when Ch'rell enslaved them in "Same as it Never Was".
2003 Video Game Series
- Slashuur: Originally, the Turtles fought this samurai-esque warrior, as he is a bounty hunter, and was hired to attack them. However, after a couple of encounters, the Turtles learn that he is actually an Utrom whose family was attacked and killed by The Shredder/Ch'rell. He then assists the Turtles in attacking The Kuraiyama. His name is reminiscent of The Shredder's, with the two "u's" possible to emulate the double "d" in The Shredder's name. He appeared only in the video game TMNT 2: Battle Nexus.
- Councilor Drexl
- Lieutenant Kleve
- General Krang
- Larqa: An Utrom scientist
- Leeshawn: Technical Specialist
- Lorqa: Former senior member of the Utrom High Council.
- Lieutenant Sulfurch
- Ma’Riell: Chief Science Advisor
- Corporal Montuoro
- Quanin: Krang's father and an Utrom warlord
- Yoom: Utrom who took a DNA sample from a triceratops.