Deliberate "mistake": When Tarzan fights with the leopard, it scratches his chest. However after they fall into the pit and Tarzan comes out carrying the dead leopard, the scratches on his chest have amazingly healed. [It is a long-standing Disney tradition that no evidence of violence is shown on screen. Still a mistake, but there's why].

Factual error: When the humans are capturing the gorillas, Clayton fires about 15 rounds on his shotgun. This is pretty impressive, considering this is the early 1900's.

Continuity: When child Tarzan jumps in the lake with the elephants the water is only up to the elephants' feet, but the underwater shot shows the elephants swimming.

Continuity: When Kala (Tarzan's ape mother) finds baby Tarzan at the house on the tree she also finds a portrait of his dead parents which has the glass broken. Later on the film, the glass is perfectly OK before Tarzan steps on it and breaks it once again.

Factual error: During the song "You'll be in my Heart", lemurs are shown in the tree that Kala and baby Tarzan are in. "Tarzan" is set somewhere in Africa's equatorial jungle, as this is the only place gorillas live. Lemurs are native to the island of Madagascar.

Continuity: After Tarzan fights the leopard, and at the point when the gorillas and him run off, the dead leopard is missing.

Continuity: When Tarzan decides to become the new leader of the apes, his hair is waving in a strong wind, but the rain is pouring straight down.

Continuity: When Clayton is drawing on the chalkboard his shotgun is leaning against it. After Tarzan takes the chalk and draws all over the chalkboard, the gun has disappeared.

Continuity: When Tarzan says "A hair?" and Terk replies "Yeah, a hair", their hair is blowing in different directions with the same current of wind.

Continuity: When Jane and Tarzan return to the camp and the ape knocks Jane down, she picks up a ladle.  The first ladle is bent and then the next shot shows a straight ladle, and then the bent one is back.

Continuity: In the scene where Jane is telling her father about Tarzan, and Clayton calls it a "girlish fantasy", Tarzan jumps into the camp. Throughout the entire scene, Jane's hair was slightly tied back, but when Tarzan comes very close to her and says "Jane", it's down. The next shot it's slightly up again.

Plot hole: Kerchack is mad with Tarzan because he showed Jane, Porter and Clayton to the gorilla's current location. Yet Kerchack does not move the group even though he obviously knows they're no longer safe there.