Movie Goof (continuity error): When Jon is driving into his driveway after picking up Odie, you can see into the back seat of the car and see that Garfield isn't there.
Movie Goof (continuity error): The night Garfield gets kicked out of his house and has to sleep on the porch, he looks into a window and sees Odie sleeping on the bed with Jon with no collar on. At one point when Odie is out on the porch with Garfield, he has the collar on. Then, when Odie runs off the porch to chase a scooter, the collar is gone again.
Movie Goof (continuity error): When Odie walks up to Mrs. Baker's door, he walks up six steps. Later in the movie, when Jon and Liz leave the same place, they only walk down one step.
Movie Goof (continuity error): While Liz is running through the train station she has heeled shoes on. In subsequent shots, she is wearing different shoes with no heels .
Movie Goof (revealing mistake): When Garfield uses the remote to electrify Happy Chapman in the train station, he pushes somewhere on side of the remote control where there are no buttons, but the lights that signify the collar's activity.
Movie Goof (continuity error): The cat/dog flap changes from one painted the same color as the door to clear. Although the cat/dog flap might be a model where a plastic board can be inserted to lock the door in one scene it changes between shots with no time for anyone to change it.
Movie Goof (continuity error): Before Happy Chapman is approached by the dogs, cats, and rats he wraps the electric collar around Odie's neck, although he doesn't appear to fasten it. In the next few shots, the collar switches back and forth between Odie's neck and Chapman's hand.
Movie Goof (continuity error): In the pound, the cat in the cage to Garfield's right changes between shots.
Movie Goof (continuity error): When Happy Chapman's assistant looks out the window from the clothing store, it is raining heavily. However, when they leave, it is sunny and dry.
Movie Goof (errors in geography): When everyone escapes from the animal shelter, a comment is made by a dog about the fire hydrant located right outside the door. The fire hydrant is a "wet barrel" model which is used in warm weather locations. The mid-west uses "dry barrel" hydrants to prevent freeze damage.
Movie Goof (continuity error): When Garfield is trying to stop the trains, the positions of the three levers on the train control table change constantly between shots.
Movie Goof (continuity error): When Happy Chapman is leaving the studio with Odie for the train station, the elevator he is taking is going up not down.
Movie Goof (revealing mistake): When the table with the bowling ball falls, you can see the wire that pulls it.
Movie Goof (continuity error): When Happy Chapman throws his antiallergic medicine on the table in his bureau, it disappears in subsequent shots.
Movie Goof (continuity error): In the vet's office, when Garfield is carried into the grooming room, there are close-ups of two cats in cages which do not appear in the long shots.
Movie Goof (continuity error): When Jon throws Garfield out of the house because it is wrecked, Garfield scratches on the door and you can see there isn't a cat door anywhere on the door. Yet after Garfield's song, Odie climbs out of a pet door on the same front door.
Movie Goof (continuity error): In one of the scene when Jon's car is in his driveway, the license plate is not the generic I35 749, but in the next scene it changes back.
Movie Goof (factual errors): Garfield enters the train control room at Los Angeles Union Station when the only employee in the room leaves the room. There would always be someone in this room when the trains are in operation.
Movie Goof (continuity error): Happy Chapman is allergic to cats, but never sneezes or shows any signs of his allergy on the two occasions he is in a room with Garfield.
Movie Goof (continuity error): When Happy Chapman leaves the Telegraph Tower, Odie is wearing the electric collar. But when they enter the train station, the collar isn't around Odie's neck, but in Happy Chapman's pocket (as we see later).
Movie Goof (continuity error): Every car in the city has the same license plate number: I35 749.