Voiced by: Rob CorddryScorch's older brother and the head of mission control at BASA.
- Badass Boast: "In a galaxy filled with nerds, I'm their king."
- Big Brother Instinct: Despite all the crap he had to put up with Scorch, Gary will do anything for his little brother's safety.
- Classical Anti-Hero: He's scrawny and thought to be coward by his own brother. He manages to mature out of this.
- Geek Physiques
- Nice Guy: A lot more humble and sensitive than his brother.
- "Well Done, Dad!" Guy: Gary desperately wants Kip to look up to him and is saddened by how his son looks up to Scorch.
Voiced by: Brendan FraserGary's younger brother who is an arrogant but benevolent space pilot.
- "Awesome McCool" Name: With a name like Scorch Supernova, you can't help but expect awesomeness.
- Big Little Brother: He's the younger of the two brothers, but is taller and broader than Gary, leading many to assume he's the oldest.
- Catch-Phrase: "Scorch me, baby!"
- Chick Magnet: Implied. A line from Gabby indicates that a number of women are attracted to Scorch.
- Cool Uncle: To his nephew, Kip. He dedicated Earth to him.
- Dumb Muscle: Scorch may have the strength, agility, and courage, but he lacks the focus and rationality.
- Friend to All Children: His scene with Baab babies and relationship with Kip solidifies him as one.
- Living Legend: Given the statue of gold built in his honor.
Voiced by: Sarah Jessica ParkerGary's wife and Kip's mother.
- Action Mom: Kira has not lost her edge after becoming a mother.
- Nice Girl: The least snarky one in the cast and commentary states she wants to fix the pain that's happened in her family.
- Retired Badass: Kira retired from BASA so she could focus on being a mother. But, don't underestimate her.
Voiced by: Jonathan Morgan HeitGary and Kira's adventurous son and Scorch's nephew.
Voiced by: Craig RobinsonA mouse-like alien who Gary befriends and weds Scorch and Gabby at their wedding. He hosted a radio show on his planet that got so famous that he invented the social networking service.
- Deadpan Snarker: The most sarcastic in the movie, second only to Gary.
- Hates Being Touched: He reacts badly when Scorch strokes him like a pet.
- Meaningful Name: Doc is a radio talk show therapist.
- Miles Gloriosus: He likes to act like he's brave and unshakeable, but often runs and hides when trouble comes.
Voiced by: George LopezA 3-eyed slug-like alien with 4 arms who Gary befriends and becomes his cellmate at Area 51. He was a professor on his planet where he had invented touchscreen technology.
Voiced by: Jane LynchA giant cyclops-like alien with anger management issues who Gary befriends. She worked as a librarian on her planet until she got so mad at looking up stuff for her kind that she invented the web search engine.
Voiced by: Sofía VergaraAn anchorwoman on Baab and Scorch's girlfriend.
Voiced by: Jessica AlbaBASA's no-nonsense chief.
General Shanker Saunderson
Voiced by: William Shatner, Joshua Rush (younger)The villainous head of Area 51.
- Alliterative Name
- Bald of Evil: Which he covers with a wig when he talks with Lena.
- Big Bad
- Disproportionate Retribution: He wants to wipe out all aliens because the grays accidentally crashed their flying saucer on his father.
- Fantastic Racism: He despises all aliens.
- Freudian Excuse: See Disproportionate Retribution above.
- Manipulative Bastard: He feigns romantic interest in Lena so she will send him Scorch (unwittingly carrying the flubonium Shanker needs for his weapon).
- Strong Family Resemblance: To his father.