Continuity mistake: At the end of the episode everyone is having a picnic. Joe says what the heck happened to that trophy and everyone's plates disappear. The table is completely empty.
Continuity mistake: Brian and Stewie see Meg enter Mayor West's motel room. She's wearing a purple dress. They follow them to a restaurant and Meg has her regular hat and outfit on.
Family Guy Viewer Mail #1 - S3-E21
Continuity mistake: When Peter is on the couch talking to Catherine, the amount of wine in his glass keeps changing from shot to shot. He takes a drink and the amount stays the same.
A Very Special Family Guy Freakin' Christmas - S3-E16
Continuity mistake: The wreath on the inside of the door changes from small to big. Notice when Peter goes outside to get a tree. Its bigger when he comes back inside the house.
Whistle While Your Wife Works - S5-E5
Continuity mistake: When Lois is helping Peter get his work done while he has the hand injury, Peter gives Lois the flip book to proofread. During this scene the phone power cord appears then disappears, and the door knob as well as the kick plate vanish then reappear properly.
And Then There Were Fewer - S9-E1
Continuity mistake: The beginning of the episode shows the front of the house. A few seconds later Peter walks in the front door with mail even though he wasn't outside before.
Continuity mistake: Peter goes to see his mom. She's drinking coffee and puts the cup down on the table to answer the door. In the next shot the cup disappears.
Continuity mistake: When the guys are arguing over the trophy Quagmires teeth disappear for 10 seconds. His mouth is all black then they reappear.
Continuity mistake: As Peter makes a comment on Jesus' joke, the screen goes into a closeup between the two of them. The potatoes on their plates change from a sandy yellow to white and the next time their plates are in view, the potatoes are back to their original colour. (00:11:33)
Petergeist - S4-E26
Continuity mistake: Lois slaps the skull out of Peter's hand and it lands on top of the dirt pile. They both turn around to look at the house and the skull is nowhere in sight.
Continuity mistake: At the start of the episode there's no coffee table beside the couch. When Brian is trying to prove to Peter that he has gravitational pull because of his weight, there's now a table with a bowl of fruit and a book.
Petergeist - S4-E26
Continuity mistake: The filing cabinet that was beside the TV moves to the corner beside the desk.
Continuity mistake: When Lois is handing out everyone's lines for the play, Meg doesn't have glasses on. Split second later they appear. (00:09:47)
Continuity mistake: When Lois opens the door to Peters mum, Peter appears at the door and Lois simply vanishes. (00:05:00)
Continuity mistake: When Lois is talking to Brian about having homicidal thoughts, the rug colours swap order. (00:14:20)
Continuity mistake: At the start, Chris' hat is all yellow instead of yellow and black. (00:00:30)
Brian Writes a Bestseller - S9-E6
Continuity mistake: When Stewie answers the door, notice the doorknob. It's down further in just this scene, so he can answer it. The rest of the episode it's where it's supposed to be.
Continuity mistake: Lois and Brian go outside and celebrate Peters dads death. Behind them you see the trash cans. They come back in and sit down and the trash cans have vanished. (00:12:33 - 00:12:54)
Peter, Peter, Caviar Eater - S2-E1
Continuity mistake: When Brian is holding Peter's Star Wars glass, it continually spins and changes positions in his hand between shots, with the figures painted on it being in different directions. (00:17:32)