Lizzie Devine
Occupation	Numbuh 1's ex-girlfriend
Voice	Grey Delisle
Appearances	Operation: L.I.Z.Z.I.E. Operation: Q.U.I.E.T. Operation: D.A.T.E. Operation: C.A.K.E.D.-T.W.O. Operation: L.E.A.D.E.R. Operation: R.O.B.B.E.R.S. Operation: N.U.G.G.E.T. Operation: P.O.O.L. Operation: L.U.N.C.H. Operation: S.N.O.W.I.N.G. Operation: F.E.R.A.L. Operation: H.O.L.I.D.A.Y. Operation: R.E.C.E.S.S. Operation: W.H.I.T.E.H.O.U.S.E. Operation: G.I.R.L.F.R.I.E.N.D.
Cameos	{{{Cameos}}}

Lizzie Devine is Numbuh 1's overweight and overbearing girlfriend. She first appeared in the self-titled Operation: L.I.Z.Z.I.E., in which she uses a mind control helmet on her boyfriend in order to stop him from spending time with the Kids Next Door. In subsequent episodes, Lizzie is largely a neutral character. Lizzie has the same character model as one of the Delightful Children From Down The Lane. This was only referenced in-series in Operation: C.A.K.E.D.-T.W.O., when she was bribed with the promise of a taste of the frosting on the Delightful Children's cake to dress up as one of them. She also has bad cooking skills, such as making a pie that knocked out Numbuh 2 and Numbuh 3 and soup that almost poisoned Numbuh 1.

Lizzie is extremely obsessive and possessive in concern of her boyfriend, and is very demanding and even threatening of "Nigie" when she wishes to spend time with him, even when he is clearly occupied with more urgent matters. This behavior frequently causes problems for Numbuh 1 and the rest of Sector V during missions. Once she was so protective she even had the nerve to say "SHUT UP!" to the Delightfuls.

In Operation: D.A.T.E., she earned the temporary position as Numbuh 49 when Numbuh 1 told her coming to the dance was a mission. She appeared completely oblivious to the Delightful Children From Down The Lane's brainwashing of all the party guests and insisted on having her picture taken even after it became obvious that the camera was a brainwashing device. {C {C After that, when Nigel hurts her feelings and said that it was never a date and didn't care if she thought so, and was seen sad after Nigel slammed the door right in front of her face. Right before the Delighfuls were about to delightfulize Nigel, Lizzie stepped in with a glass of cherry punch from the party and shouted, "NIGEL UNO! I'D LIKE A WORD WITH YOU!". The Delighfuls asked what the meaning of this was, but Lizzie was so angry and just replied rudely and loudly, "SHUT UP!". After Lizzie gave a speech to Numbuh 1, she tried to wet him with her punch, but he jumped out of the way and the punch landed on the master fuse box. Numbuh 1 grabs Lizzie and hugs her, telling her that she's brilliant. She replies by saying, "Now, was that so hard?". Outside, the mansion blows up into fireworks as they and the Delighfuls run outside as the mansion is destroyed because of Lizzie's glass of punch.

Their relationship is not entirely one-sided, however, and Numbuh 1, while frequently annoyed by Lizzie's antics, seems to genuinely care for her and usually makes up with her for whatever animosity has ensued at the end of the episode. However every other member of the KND tend to groan everytime she appears.

At the end of Operation: G.I.R.L.F.R.I.E.N.D., Lizzie breaks up with Nigel after he leaves her several times during their date to attend to the imminent danger present to them, courtesy of the KND Splinter Cell. Also, she was tired of Numbuh 1 always putting the Kids Next Door before her and not spending enough time with her.