What is the title of Pixar’s first Cars short-film series featuring Mater’s stories?

Pixar’s first Cars short-film series featuring Mater’s stories is Mater’s Tall Tales.

The series, officially titled Cars Toons: Mater’s Tall Tales, follows Mater as he tells elaborate stories about adventures from his supposed past. Each story usually presents Mater as a remarkable hero, while Lightning McQueen reacts to the increasingly unlikely claims. The shorts use comedy, exaggeration, and familiar characters from Radiator Springs.

The series debuted in 2008, between the releases of Cars and Cars 2. Its title is a pun on “tall tale,” meaning an exaggerated story. Cars Toons is the broader brand name for Pixar’s Cars shorts, while Mater’s Tall Tales identifies this particular recurring format. That distinction makes the full series title the most precise answer.