Belgarath is a fictional character in the David Eddings book series The Belgariad followed by The Malloreon. He is the father and ultimate grandfather, respectively, of Polgara and Belgarion. He began as a young orphaned thief thousands of years ago, named Garath, who after visiting one of the lost tribes of man, found himself in the Vale of Aldur. Caught there in a snowstorm and dying, he was leaning back and feeling sorry for himself when invited inside of a tower. He went inside, planning to steal, and found himself given tasks to do for the owner. He eventually discovered the power of the "Will and the Word", also known as sorcery, and became a disciple of the tower's owner, one of the Seven Gods named Aldur, who renamed him Belgarath, the "bel" meaning "beloved".

He is sent on a number of missions throughout the world, dealing with issues that Aldur wishes a human representative to see to. He comes across a young she-wolf in his travels, while travelling in the form of a wolf himself, and she follows him to his errand and back to his tower. After hundreds of years, she sees him turn into a man, and changes her form to an owl and flies away. She builds a farmhouse in the Vale and Belgarath stumbles on her and finds out her name is Poledra. He doesn't realise who and what she is and marries her, and they have twin girls. One of these girls is Polgara, and the other is Beldaran.

During his later travels, after the apparent death of his wife, he goes by the name "Old Wolf" and helps his sorceress daughter Polgara protect the last of the royal line of Riva, as well as opposing the evil, one-eyed god Torak. It is under this alias and under the guise of a storyteller that he is first introduced to the protagonist of "The Belgariad," a boy named Garion who is a descendent of Beldaran and the Rivan kings in Polgara's care.