Stewie: "You know, mother, this could almost have passed for a palatable banana pudding, but without Nilla wafers it's just another one of your wretched culinary abortions. Now clean it up!"
Stewie: Heavens, you don't so much speak the language as you chew on it and spit it out.
Stewie: Nothing says "Obey me" like a bloody head on a post.
Stewie: Yes, I rather like this God fellow. He's very theatrical, you know, a pestilence here, a plague there. Omnipotence. Gotta get me some of that.
Stewie: "Hey, mother, I come bearing a gift. I'll give you a hint. It's in my diaper and it's not a toaster."
"My, my, what a thumping good read. Lions eating Christians, people nailing each other to two-by-fours. I say, won't find that in 'Winnie the Pooh!'" -Stewie reading the Bible
"I love God, he's so deliciously evil!" -Stewie
While trying to potty-train Stewie
Peter: Maybe you don't have to pee. I'll just give you some beer, it'll run right through you.
Stewie: Beautiful. And while we're at it we can light up a dubey and watch porn!
Lois: "Oh, Stewie, you're adorable."
Stewie: "Yes, yes, I rather like the sash, but do the Huggies make my ass look big?"
Girl: You are the weakest link. Goodbye!
Stewie: Oh gosh that's funny. That's really funny. Do you write your own material? Do you? Because that is so fresh. "You are the weakest link, Goodbye!" I've never heard anyone make that joke before. Mmm. You're the first. I've never heard anyone reference, um reference that outside the program before. Because that's what she says on the show, right? "You are the weakest link, Goodbye!" And yet you've taken that, and used it out of context, to insult me in this everyday situation. Gosh, what a clever, smart girl you must be, to come up with a joke like that by your self. Mmm. That's so fresh, too. Any Titanic jokes you want to throw at me while we're hitting these phenomena at the height of their popularity? Because I'm right here. God you're so funny!
Stewie: Uuhhhhh, what the hell do you think you're doing?
Brian (the dog): I'm cleaning myself.
Stewie: Uh, you were clean 15 minutes ago, now you're just on vacation
Stewie: Wooh, Lois, someone's wearing their ovaries on the outside
Stewie: HA... HA... HA... HA...
Eliza: Ewww, your breath smells like kitty litter
Stewie: I was curious!
Lois: What's going on?
Stewie: We're playing house.
Lois: The boy is all tied up.
Stewie: Roman Polanski's house.
Stewie: Oh I feel so delightfully white trash! Mommy, I want a mullet!
Stewie: I'd do her... do her... wouldn't do her.... Whew! who hasn't done her?! ...Lose the pigtails and we'll talk...
Stewie: "Yea, and God said to Abraham, 'You will kill your son Isaac.' And Abraham said, 'I can't hear you, you'll have to speak into the microphone.' And God said, 'Oh, I'm sorry, is this better? Check, check, check. Jerry, pull the high end out, I'm still getting some hiss back here.'"
Stewie: "Damn you, vile woman! You've impeded my work since the day I escaped from your wretched womb. When you least expect it your uppance will come!"
"I say, Mother, this hot dog has been on my plate for a full minute and it hasn't yet cut itself." -Stewie
"Honey, I'll be right there." -Lois
"Oh, by all means, take your time. Oh, and when you do finally get around to it, I'll be the one covered in flies with a belly that protrudes half-way to bloody Boston!" -Stewie
Stewie: "What the hell is this?"
Lois: "Sweetie, that's tuna salad."
Stewie: "Oh, is that what it is? Really? Because I could have sworn it was mayonnaise and cat food."
Stewie: "Oh, this is just so good it has to be fattening."
Lois: "Stewie, did you unhook mommy's bra?"
Stewie: "Flappy, good news, I've decided not to kill you."
Stewie: "What's this? Blueberries! Oh, oh my G... oh, that's better than sex!"
Stewie: "Good God, I've been adopted by a Benetton ad!"
Stewie: "Oh, hosanna, it's the lesser of two evils!"
Stewie: "You! Heat up some gravy for our guest. My last helping of white meat was drier than Oscar Wilde."
Stewie: "It seems with death incapacitated my matricidal efforts are futile."
Stewie: "You know, mother, as first lady of the American stage Helen Hayes once said, I'm going to kill you."
Stewie: "You know, it is so fashionable to take a shot at Jay Leno. Look, the fact is the man is out there every bloody night with fresh material and he's charming."
Stewie: "How positively delightful! It's as if someone stabbed Mr. Bubbles."
Stewie: "Does this not disgust you?"
Brian: "Kid, you're talkin' to a guy who uses his tongue for toilet paper."
Stewie: "I miss my mommy. Yes, yes, I also miss colic and rectal thermometry."
Stewie: "Damn, damn, damn, damn. I've grown accustomed to her face...."
Stewie: "Oh, Cupid, hath thou pierced me with thine sweet searing arrow. Stomach, cease thy lustful quake."
Stewie: I say, if you find a human skeleton with a Lincoln Log jammed in the temple, I didn't do it. But I need that log back to finish my recreation of James Madison's cabin.
Brian: "Ah, the old alma mater. I tell you, there's something magical about Brown. Chris: "Brown is the color of poo. Ha ha ha!"
Brian: "Yes. Yes it is."
Lois: "Oh, I haven't been on a college campus in years. Everything seems so different."
Stewie: "Really? Perhaps if you laid on your back with your ankels behind your ears that would ring a few bells."
Co-ed: "Are you in a fraternity, little boy?"
Stewie: "Not yet, but I'm think of joining I Felta Thigh."
Stewie: "If I could build a device to harness the size of that leviathan, there'd be no limit to what I... Oh my God, there's an orgy in my mouth!"
Stewie: "I say, Rupert, this paste is quite delicious. It's almost worth the bowel obstruction."
Stewie: "Remind me to ask the doctor when my other testicle is going to descend."
Stewie: "I was pink as a pistol! Pink as a pistol? Good lord, I can't even form a cogent simile anymore."
Stewie: Look at him. He runs like a Welch man. Doesn't he? Doesn't he run like a Welch man?
Stewie: Easy! Massage the scalp. You're washing a baby's hair, not scrubbing vomit off your Christmas dress, you holiday drunk.
Meg: Everybody! Guess what I am?
Stewie: Hm, the end result of a drunken back-seat grope-fest and a broken prophylactic?
Stewie: I smell a messy diaper. God, why does that turn me on?
Stewie: Let me guess, you picked out yet another colorful box with a crank that I'm expected to turn and turn until OOP! big shock, a jack pops out and you laugh and the kids laugh and the dog laughs and I die a little inside.
Stewie: For the future, you came on a little strong.
Stewie: Oh my, how ruthlessly absurd.
Mrs. Pewterschmidt: Would you like a piece of candy?
Stewie: I smell death on you.
Stewie: I needn't fear this Santa. He if he were truly omnipotent he'd have the testicular fortitude to show himself!
Stewie: By all means, turn me into a child star. Perhaps I can move to Californ-i-ay and wrangle me a three-way with the Olsen twins.
Stewie: Thank you, thank you... that was me farting... by Chopin.
Stewie: I have an army to raise and I must get to Managua at once! I require a window seat and an in-flight Happy Meal. But no pickles! Oh, God help you if I find pickles!
Stewie: "well, well mother, we meet again"
Stewie: "You know Mother, life is like a box of chocolates [he presents her with a box], you never know what you're going to get, your life however is more like a box of active grenades! [the box has grenades in it] Now I offer you one last chance for deliverance- return my mind control device, or be destroyed."
Stewie: "Forecast for tomorrow: A few sprinkles of genius with a chance of doom!"
Stewie: "Hello mother, care to partake in one of your oh-so-exhilarating games of Peek-a-boo?"
Stewie: "What's your email? Mine is loismustdie, all one word, @yahoo.com."
Stewie: "Ah, the breakfast thing. Yes, it wasn't about the eggs really, frankly I like the yolks, I..I don't..I have no problem, it's, there's always been a lot of tension between Lois and me and it's not so much that I want to kill her. It's just that I want her not to be alive anymore. I sometimes wonder if all women are this difficult, and then I think to myself, by god wouldn't it be marvellous if I turned out to be a homosexual."
Bonus Quote from Family Guy:
Gun Activist: Drugs don't kill people, dangerous minorities kill people.