Big Brother is a giant teenage villain who is a brutal member of The Teen Ninjas who is based on the common archetype of the abusive older brother. He first appears in Operation: M.I.N.I.-G.O.L.F. where he is defeated by Numbuh 2. In Operation: M.O.V.I.E., Big Brother apprehends Numbuh 4 when his disguise is blown.
- Big Brother's name comes from George Orwell's book 1984, although he is completely different from the Big Brother in that story.