Charlie's Grandparents are supporting characters in the 1964 Roald Dahl novel Charlie and the Chocolate Factory and it's various adaptations and in it's 1972 sequel Charlie and the Great Glass Elevator. They are grandparents of Charlie Bucket.
They are shown to be caring grandparents to Charlie, as they are always happy to see him and are willing to give him their portions of food, which he doesn't want to accept because he cares for them also. They are shown to hate kids with spoiled attitude, as shown in the book and in the 2005 movie as they insulted all bad kids after hearing about their interviews in which they were jerks. Joe Bucket better known as Grandpa Joe is the one who loves Charlie the most of them all and was the most hopeful that Charlie's dreams will come true and did everything to make him happy.
In the book sequel, all of them were scared of Willy Wonka's crazy behavior, except Grandpa Joe, who already knew how crazy Willy Wonka is.