Continuity mistake: When Zira is singing "My Lullaby" the cut on her ear is on one ear, then the other, then back again. It does this four times by the end of the song.
Continuity mistake: When Nuka and Vitani are at the Elephant Graveyard igniting their sticks to set the Pridelands ablaze, Vitani is first drawn with dark ear stripes. There is a close-up of her rolling her eyes at Nuka and the ear stripes are still colored in, but the lines indicating where they are present. When the stick ignites and Vitani grabs it, the stripes are gone. The stripes then appear when Vitani is setting some dry grass on fire. This mistake is repeated throughout the film.
Continuity mistake: At the end, just before the final fight scene, Zira's pride is lined up with Zira in the centre on a rock, placing her above the others. Shortly after you see a close up of her with a couple of lionesses beside her - at the same height as her. They disappear in the next shot of her.
Factual error: Near the end of the song "One Of Us" when Kovu is exiled, the beisa oryx at the front of the animal chorus (the one shaking her head slowly) has incorrect facial markings for her species. The other beisa oryx in the background has the correct markings. When she sings "He is not one of us," solo, she has correct facial markings, but lacks the correct leg markings, which she had when her facial markings were incorrect.
Continuity mistake: During the final battle, the number of lionesses changes dramatically. When the two clans are standing in line, there are dozens on both sides. However, when Kovu and Kiara see the battle from across the gorge, there only appear to be ten at most. Also, both Zira and Simba are gone as well as any of the existing land formations (Such as Zira's rock).
Continuity mistake: At the end in the scene directly after Zira falls into the water, Kovu's scar is missing.
Continuity mistake: When Rafiki is in the tree and Mufasa formulates a plan, there is a gourd that falls and breaks and Rafiki then picks up to symbolise the plan. Then he says "Are you crazy? This will never work!" and makes a hand gesture, meaning that he dropped the gourd pieces. However, they are not visible in the overhead shot when he says, "I just hope you know what you are doing!"
Continuity mistake: The bite mark/scar on Zira's ear changes ears throughout the movie.
Continuity mistake: During 'Not One Of Us', the vultures have shadows when they are near the lion. However, in the next shot, no shadows are on the lion's body.
Other mistake: Near the start of 'Not One Of Us', animals are stomping their feet at Kovu. There is a gazelle towards the bottom right-hand-side that does this while raising both front legs and having their hind right leg not on a proper surface (looking closely, it's actually floating on nothing). No animal could do this without falling over.