Continuity mistake: When Homer is writing a note to Marge, he scribbles out Patty's name and writes his own name directly beneath it. When Marge reads it, Homer's name is under Patty's, but slightly to the right. (00:14:30)
Team Homer - S7-E12
Continuity mistake: During the classroom scene where Bart reveals his Mad magazine shirt, he removes his sweater and puts it on his desk. In the next shot the sweater disappears. (00:03:40)
Sweets and Sour Marge - S13-E8
Continuity mistake: When Lou throws a small chocolate statue in the fire, his skin is yellow when it is usually brown.
Marge vs. the Monorail - S4-E12
Audio problem: When goes to the Monorail Café, the woman there says to Marge "Go away" but her mouth doesn't move.
Homer's Triple Bypass - S4-E11
Continuity mistake: When Dr Nick visits Homer for the first time, he leaves the door open. But later before the reporters come to the door, the door is closed. (00:13:40)
Brake My Wife, Please - S14-E20
Continuity mistake: Whilst Moe is talking to himself about going back to barber college the door to his bar is wide open. When the shot changes to him when he says "Who the hell am I talking to?" the door has suddenly closed. There was not enough time for it to close between shots.
Home Away From Homer - S16-E20
Continuity mistake: For "Home Away From Homer": Bart looks out his bedroom window and sees the college girls doing sexual actions in the Flanders' spare bedroom. But, there is never a window in Bart's room that could possibly face the Flanders' house. [Bart's window in many episodes does face Flander's house but in other episodes like "Bart's Friend Falls in Love" and "Bart the Mother" it faces the treehouse which is the backyard of the house.]
Continuity mistake: After Homer is shot with the cannon for the first time, the cannonball disappears from behind him.
On A Clear Day I Can't See My Sister - S16-E11
Continuity mistake: For "On a Clear Day, I Can't See My Sister": Throughout the episode, the backyard alternates between having a fence at the end and a forest at the end.
Factual error: You wouldn't hear a dial tone on one side of the phone line if the phone on the other side was cut from the receiver. You wouldn't hear anything.
Continuity mistake: In one scene Bart is swinging on a washing line then we see Homer talk to Marge and he says "He'll soon get tired of it" then it goes back to Bart and he is facing the opposite direction and he is swinging on two washing lines. (00:04:22)
I, (Annoyed Grunt)-bot - S15-E9
Continuity mistake: At one point in the cycle shop, Homer has his hand in his pocket in one shot, and it's suddenly out in the next one.
Hunka Hunka Burns in Love - S13-E4
Continuity mistake: When they are sitting down in Stu's Disco, there is a little glass next to Mr Burns' glass which vanishes in later shots.
Margical History Tour - S15-E11
Continuity mistake: Lisa empties a glass of red wine that she previously poisoned with sleeping potion. When she falls over sound asleep, her glass is shown on the ground next to spilled wine.
Continuity mistake: When Lisa is explaining to Marge why she is unhappy, the door to her bedroom closes on its own. (00:07:10)
Other mistake: When Homer talks to Bart and Lisa through the window, he is standing almost straight up, but considering he is right in front of the TV in the next shot, he would've had to crouch down a little. (00:03:50)
Continuity mistake: When Homer calls the Fatherhood Institute about his poor test results, the guy is holding a cup with 'Super Dad' on it. In the next three shots the cup has jumped to being on his desk. (00:08:50)
Lisa's Pony - S3-E8
Audio problem: When Homer is crying after the tape is finished, what he says doesn't match his mouth. (00:07:25)
Continuity mistake: When the family are on the conveyer belt in the Knowledgeium, Homer turns round and grabs the handrail (after the Troy Maclure announcement) and his fingers are just touching the rail. In the next shot his hands are clasped to the rail.
The Boy Who Knew Too Much - S5-E20
Continuity mistake: When Homer and Bart see each other skipping work/school, Homer is eating a donut then drops it on the pavement when he sees Bart. In the next shot of both of them the donut has disappeared.