Malcolm: You want to know the best part about childhood? At some point, it stops.

Malcolm: You're talking about joining a cult, Reese!
Reese: My name isn't Reese anymore.
Malcolm: Then what is it?
Reese: I don't remember, but it's not Reese!

Malcolm: [referring to Dewey] I don't believe this! Here I'm supposed to be the genius, and I'm being outsmarted by someone who can't tie his own shoes!

Malcolm:[first line] Ok, here's the thing about my family: we don't go on a lot of outings together. But when we do, there's a little tradition that we always end up observing.
Hal:[talking to the security guard] When you say lifetime ban, I mean who's lifetime that you're talking about.
[Lois drags Malcolm and Reese by the ear while the security guard sends Hal on his way.]
Lois: Don't you ever ask me for anything ever again. I should've just given birth to chimps, then at least I know to expect this kind of behavior.
Malcolm: Believe it or not, I actually envy Dewey. He got to stay home and play with the babysitter.

Mr. Woodward, Reese's history teacher: I just don't think you'd throw away the son who achieves for, well, Reese.
Lois: You don't think I'd sacrifice this one? Let me explain something to you. I would sell Malcolm down the river in a heartbeat to save Reese. Malcolm's gonna be fine no matter what happens. Maybe he'll have to go to junior college or start off blue collar, but he'll work his way up to management eventually. Reese is the one who needs saving.
Woodward: I don't believe you. No mother could ever be that callous to her own son.
[Francis appears in the window, pressed against the glass, while rain pours down and lightning flashes.]
Francis: Mom, please let me come home! I'm cold and I'm hungry! Please, I'll fix the roof, I'll paint the house! I'll do anything, Mom, please! Just let me live indoors, Mom! Please, I wanna be warm again! MOM, PLEASE! (sobbing)
[Lois smiles victoriously. Woodward looks rather apprehensive.]
Woodward: Maybe we can work something out.

Mrs. Griffin: (as she is driving, she feels an itch inside her cast and let's go of the steering wheel) Ooh, damn cast itches like a Greek sailor. (Malcolm tries to turn the wheel) Stop pawing at me!

Officer: There's no sign of forced-entry. You don't have any idea how they could have got inside?
Hal: It's a mystery.
Dewey: You left the window open.
Hal: ...Mystery solved!
Officer: What are you doing here again?
Hal: We're watching the owner's cat.
Officer: I don't see a cat.
Hal: We're not doing a very good job.

Patty (about Francis): He was so nice, and so cute.
Reese: Yeah, I'm a lot like him.
(Malcolm rolls his eyes)

Patty (to Malcolm; on the phone with Francis) Francis? Is that Francis? Tell him it's Patty Henderson from 8th grade algebra.
Malcolm (to Francis): Patty Henderson says hi!
Francis: Oh, my God! Patty Henderson is your babysitter?!?!
Patty: Let me talk to him. Hi!
Francis: Don't let her... Hi... Patty!

Patty: Hungry?
Malcolm: I don't know what I am.

Reese [about Dewey's purse]: Dewey, you're wearing an invitation to an ass-kicking!

Reese [about Dewey]: Hehe. He's cute! I hate him for being cute!

Reese [to Dewey]: Dewey, I don't think you understand. Boys like me, we look at things like this. We see normal boy, Normal boy, and boy with the purse. Which one do you think we are going to hit?
Dewey: Is one of them fat?
Reese: It doesn't matter! That boy will be fat everyday. But the boy with the purse, he might not wear it again!

Reese [to Dewey]: You, sitting around with your big eyes and your dopey voice. I have to resist hugging you myself.

Reese [to Malcolm]: Relax. Everyone will think Josh is a thief. His parents will be tied up in court, and Emily will be thrown into a foster home where she'll bite her foster parents, who will leave her at the side of the road, and she can spend the rest of her life biting hillbillies on the interstate.