Carmen and Juni's aunt and Gregorio's sister. Introduced in the fourth film, Marissa retires as a spy after giving birth to a daughter Maria. Living with her husband Wilbur, Maria, and step-children Rebecca and Cecil. The return of the evil Timekeeper/Tick-Tock forces Marissa back into action, taking Maria with her, and soon Rebecca and Cecil become involved in the OSS.
- Action Mom: She retires after having her first kid, but she gets back into action to stop Tick Tock.
- Badass and Baby: Takes Maria on her missions.
- Pregnant Badass: Takes on Tick-Tock's minions whilst having contractions.
- Wicked Stepmother: Rebecca views her as this.
The female lead of the franchise by the fourth film, Rebecca is a mischievous prankster but is very bright and loyal to her family.
- Bratty Teenage Daughter: Acts like this to Marissa. This eventually disappears when Marissa gives Rebecca one of her birth mother's possessions.
- Brother-Sister Team: With Cecil.
- Missing Mom: Her mother is said to have passed on sometime before the events of the movie.
- The Prankster: She sets up elaborate traps as pranks on her step-mom.
- Trap Master: She uses a trap with Jet Packs to ward off Tick Tock.
Rebecca's brother. A quiet boy, Cecil is thrilled upon finding Marissa is a spy and is very enthusiastic about becoming a spy himself.
- Brother-Sister Team: With Rebecca.
- Handicapped Badass: He's hearing-impaired and has spy gadgets built into his hearing aids.
- Megaton Punch: The gadget he becomes attached to can increase his strength.
Marissa's young daughter who becomes a third Spy Kid following Rebecca and Cecil, even though she's a baby. Also nicknamed Spy Baby.
- Tagalong Kid: Her mother brings her on the mission to stop Tick Tock, and she even takes down a Mook.
Marissa's husband and father of Rebecca and Cecil. He is an Intrepid Reporter who is investigating the existence of spies in the world, unaware virtually every member of his family is a spy.
- Captain Oblivious: He has a television series where he hunts for spies, while he's married to a retired spy.
- Intrepid Reporter: As the Spy Hunter, he tries to track down spies.
- Secret Keeper: Becomes this when he finds Marissa's secret, forcing him to destroy a recording of his wife in action to save her, but is fired as a result.
The Time Keeper/Time Keeper/Danger D'Amo
The villain of the fourth film. The Time Keeper wishes to freeze time using the Armageddon Device. He doubles as Danger D'Amo, head of the OSS. He really wishes to rewind time to reunite with his father, after being trapped in time and witnessing his father age and die.
- Affably Evil
- Alliterative Name: Danger D'Amo.
- And I Must Scream: Danger was frozen in time for years, unable to move and not physically aging. All he could do was stare at his father as he grew older and died. He was freed but still remained a child and had to physically grow up whilst having the mind of a man.
- Big Bad: Of the fourth film. Or so it seems.
- Even Evil Has Standards: When he learns that Cecil is hearing impaired, he orders his Mooks to give Cecil's hearing aid back.
- HeelFace Turn
- Identical Twin ID Tag: Because he made several versions of himself due to time traveling, most of his other selves selves are mooks in masks, while Tick Tock has goggles and a high pitched voice.
- Me's a Crowd: His minions and Tick Tock are all him from different times.
- Mole in Charge: Danger D'Amo is the president of the OSS.
- Significant Anagram: Danger D'Amo is an anagram from Armageddon.
- Time Stands Still: His goal is to freeze and then rewind time.
- Time Travel: He travels back in time to try to reunite with his father.
- You Can't Fight Fate: No matter what he does, his father always dies.