Teens Next Door (or TND) is a secret organization for the best and loyal KND operatives who have turned 13 (teens). They pretend to be decommissioned or traitors so they don't blow their cover to the other KND operatives that don't know the TND exist. They are known to be "special agents" for KND, but they must pretend to join the Teens and spy on them from the inside.
- Numbuh Infinity (Leader)
- Maurice (Numbuh 9)
- Chad Dickson (Numbuh 274)
- Unknown female from the credits of the episode Operation: M.A.U.R.I.C.E.
- Numbuh 5
- Numbuh 1
- Numbuh 4
- Numbuh 2
- Numbuh 3
KND Operatives that know about the TND
- Numbuh 5 -- Found out from Maurice in Operation: M.A.U.R.I.C.E.
- Numbuhs 1, 2, 3 and 4 -- They found out in Operation: T.R.E.A.T.Y. from Numbuh 5 and Chad.
- Supreme Leader -- As the head of the KND itself, he or she would have to know about it.
- Decommissioning Squad -- Just like the Supreme Leader, the Decommissioning Squad (including the head of the squad) would most likely have to know about it in order to help chosen teen(s) fake and/or falsely escape their decommissioning(s).
- Numbuh 74.239
- Numbuh Infinity
- False decommissioning is not the only way to hide the TND; operatives, like Chad Dickson, falsely betrayed the KND to become a Teen Ninja in order to infiltrate the Teens.
- In the Rainbow Monkey Website, it says Numbuhs 60 and 362 are fugitives; this could imply they were selected to become TND operatives because of their skill. Thus, they may have also eventually feigned their betrayal in a similar way Chad did.
- It's implied in the end credits of Operation: M.A.U.R.I.C.E. that there are also undercover adult operatives for the KND, which in turn would suggest that there's an "Adults Next Door" organization.
- This is sort of (but not entirely) confirmed at the end of Operation: I.N.T.E.R.V.I.E.W.S., where it's implied that Numbuhs 1 through 5 were never really decommissioned and were allowed to remain part of the KND as undercover teen (and later adult) operatives.
- It is possible there is a Negative counterpart of the TND, known as the Destructively Nefarious Teens (DNT).
- Before the Junior High Rebellion of 1999, the decommissioning age was 16, so selected operatives migrated to the TND at age 16; however, because of the insurrection, the decommissioning age was lowered to 13. [Citation needed]
- Furthermore, it is likely there were loyalist teenagers who still defended the KND from the teenage rebels, thus after the uprising, these loyalists were rewarded positions as TND operatives for the loyalty and faithfulness.
- In contrast to what has been previously said Numbuh 362 may not have known about the TND as she seemed generally upset at Numbuh nines decommission ceremony.