What is the name of Odysseus's grandfather, the master thief?

Odysseus’s grandfather, the master thief, is Autolycus.

Autolycus is usually described as the son of Hermes, the god associated with cunning, travel, and trickery. His legendary skill was theft: he could disguise stolen animals by changing their appearance, making horned cattle seem hornless or altering their color. Some traditions also credit him with stealing Sisyphus’s herd, though versions differ on whether the theft succeeded.

Autolycus was the father of Anticlea, who married Laertes and became the mother of Odysseus. This makes him Odysseus’s maternal grandfather. In Homer’s Odyssey, Autolycus also gives Odysseus his name. During the child’s naming, he chooses a name connected with his own anger toward many people, linking the name Odysseus to the Greek verb meaning “to hate” or “to be angry.”

Laertes is Odysseus’s father, not his grandfather. Hermes is commonly listed as Autolycus’s divine father, while Sisyphus is another famous trickster who is sometimes confused with him because of their rival theft story. Autolycus is therefore the canonical answer to this question.