Who gives Anakin Skywalker his scar?

Answer 1

Scar used to be called Taka and got his scar from a water buffalo. This is official as it is explained in a book series called The Lion King Six New Adventures.

You can read the books here:

http://snowlands.ru/en/library/cat/the-lion-king-six-new-adventures.htm

Answer 2

Anakin received his scar from Asajj Ventress. Her lightsaber struck him across the eye when they were dueling on Coruscant. You can see that in the Clone Wars graphic novels: specifically "Clone Wars: Volume 6: On the Fields of Battle."

Answer 3

While battling Asajj Ventress on Coruscant he received a cut on his face by her lightsaber.

Answer 4

From a duel with Sith Asajj Ventress.