When Simba and Mufasa view the sunrise, they refer to the "shadowy place" as being on their right. As they were facing the sunrise (east) that would mean that anything on the right side would be south. And yet, Scar refers to it later as the place "beyond the northern border."
After Zazu is blown away by the hyenas he apparently alerts Mufasa that Simba and Nala are in danger and Mufasa comes to the rescue in just a few minutes but given Mufasa was in the Pride Lands it should have taken him longer to get the elephant graveyard.
When Scar first begins his speech after Mufasa's death, nine adult lionesses can be made out. However, when the hyenas begin to appear, there are suddenly only eight. The same thing happens when Simba returns to Pride Rock. At first there are six lionesses, then seven, then six again, then only five, then six.
When Timon and Pumbaa find Simba in the desert, Timon is frightened and climbs on top of Pumbaa. On the next shot we only see Pumbaa's shadow cast in front of Simba, without Timon. When we next see Pumbaa, Timon is back on Pumbaa's back.
The number of whiskers each male lion has changes from scene to scene, and sometimes the whiskers disappear altogether. None of the lionesses in the film have whiskers, though obviously in reality females do have whiskers.
(at around 40 mins) In her first appearance, Nala's mother Sarafina's toes are the same color as the rest of her body. However, when Scar is informing the pride of the accident, her toes are lighter. A second later, during Nala's close-up, Sarafina's toes are once again the same as her body.
Near the end of the film when Scar has Simba hanging on the edge of Pride Rock, the camera moves out and the lightning crashes, and we can see Simba is holding on to the rock up to his elbows, yet in the next scene we can see he is only holding on by his paws.
Rafiki leads Simba to a lake claiming to show him Mufasa. Simba looks up from the lake when he hears Mufasa in the sky. He never moves all the while talking to Mufasa, which means he should be standing at the edge of the lake. But when Mufasa fades away Simba runs forward and we realize Simba was nowhere near the lake, but on a grassland. If he was near the lake, he should have fallen into it when he ran forward.
When Mufasa and Simba are talking at the top of Pride Rock, facing the sun, their shadows stream out behind them, which is correct. However, as Simba says "Everything the light touches", his shadow is in front of him, which is wrong. It should be cast on his right. Also, in the next shot, when Simba and Mufasa are facing south towards the 'shadowy place', their right sides are in shadow, with the light shining from the left. But it is sunrise, the sun, and therefore the light, should be on their right.
In the scene where Pumbaa is grovelling before Simba, Timon walks up to him and places his hands on the center of Pumbaa's nose, between his nostrils. In the next shot, his hands are more towards the top.
When Simba comes back to Pride Rock, he looks out at it, and you can see dead trees on Pride Rock. When Nala comes and looks at it they are gone. When Timon and Pumbaa come and look at it, the trees are back, but when the storm movie in they are gone again. After that scene, the trees are there for the rest of the movie.
When Simba finds Mufasa's dead body, his tears leave stains running down both cheeks. When Scar appears, Simba's face alternates between having tear stains on both cheeks in medium shots and only on his right cheek in close-ups. Once Scar tells Simba to run away, the stains disappear altogether.
When Simba approaches Mufasa's dead body, the camera shows Mufasa from the back and his paw is clearly past his nose. But when are then shown him face on, his paw has moved to the same level as his nose.
The hyenas are seen throughout the entire film with three toes on all their paws. But when the hyenas are chasing Simba, Banzai claws at him after he squeezes through a rock, and his paw has four toes.
When Simba is talking to Scar about the graveyard, Scar says "And he's absolutely right! Far too dangerous! Only the bravest lions go there!" Scar is sitting up and looks off to the right of the screen, but in the next shot he is sitting down with paws folded.
Disappearing Tree/Rock - When the wildebeest herd starts to stampede through the valley, Simba is first on top of the rock that is under the tree, in the valley. The next scene then shows Simba standing out in the open floor of the valley as the wildebeests come running at him, and now there is no tree or rock anywhere to be seen. Then as Simba is shown running away from the wildebeests, we can see the tree and rock in the background again.
When Timon files down one of Simba's claws you can clearly see that it is very short, but in another scene, shortly after where Simba eats a grub, you can see the same claw at the same size it was before being filed down, having had no time to regrow.
Near the end of "I just can't wait to be king" when the animals start falling, an elephant lands on top of the horns of a sable antelope. But the elephants were dancing all the way at the bottom and the sable antelopes were almost at the top.
Normally, the hyenas possess only three digits. However, they get a thumb on two occasions for plot purpose: in first, Shenzi when she catches Zazu hastily fleeing from them in the graveyard. In second, Banzai when he claws at Simba fleeing from the gorge after Mufasa's death: he lets four visible scratches on the rock where the lion cub barely escapes.
(at around 15 mins) When Simba and Nala go to take place on each side of Zazu to make him faces alternatively, Simba passes in front of Zazu. However, his reflection behind on the pool merges briefly with Zazu's instead of being hidden like it should.
(at around 21 mins) When Banzai says, "Here, kitty, kitty, kitty," it may appear as though no one is actually speaking. This is because the shot cutting from the cubs to the hyenas is very quick. However, pay close attention only to Banzai's location on the screen: you see his mouth moves when he says "here," and he's audibly saying "kitty, kitty, kitty" through gritted teeth, with his lips shown curled back. If you grit your teeth, curl your lips back, and say this line, you can do so without moving your mouth and it will still sound perfect because you only need to use your tongue to make the sounds.
When Scar tells Simba "Remember, its our little secret!", Scar is standing too close to the camera for his legs to be seen, and his position is way outside the ledge and he seems to be standing in mid-air.
Simba had apparently spent years eating nothing but bugs while with Timon and Pumbaa yet he becomes a strong and well built adult instead of being malnourished due to lack of meat which is a lion's primary diet. Not only that, but his jaw would be weak and his fangs would be soft causing them to fall out.
When Rafiki parts the grass to show Simba the Dream Pool, he pulls aside the grass on Simba's right (and holds it there). However when Simba passes through the gap, the grass on his left is also pushed aside as if by some invisible hand. It springs back once he's through.
Scar Steps on Smoke - When Scar begins to sing "Be Prepared", he can be seen walking towards the camera while green smoke is billowing up around him. If you notice on the right side of the screen there is a cloud of green smoke that comes up and you'll notice that Scar's right rear foot (screen right) walks over and on top of part of the smoke.
The goof item below may give away important plot points.
(at around 1h 3 mins) Rafiki's Swahili chant "Asante sana, squash banana, we we nugu mi mi apana" does not mean "You are a baboon, and I'm not." Nor does it mean "You are a dog, and I'm not," as has sometimes been suggested. Neither the Swahili for baboon, nyani, nor the Swahili for dog, mbwa, appear in the song.