Why does Walter Cunningham follow Jem and Scout home for lunch in To Kill a Mockingbird?
Walter Cunningham follows Jem and Scout home for lunch because Jem has invited him to join them for the noon meal.
Walter Cunningham comes from a poor but proud family. They are hard workers, and will be beholden to no one, paying their debts faithfully in whatever way they can. Walter comes to school each day with no lunch, because he cannot afford one, and in his family, it is better to go hungry than to lose one's dignity. Miss Caroline, his new teacher, notes that he has no lunch and offers to let him borrow a quarter to buy some. When Walter politely refuses to take the quarter, Miss Caroline is nonplussed, until Scout volunteers the explanation that "the Cunninghams never took anything they can't pay back...they don't have much, but they get along on it". As Scout has already gotten off on the wrong foot this morning, Miss Caroline insensitively takes her remarks as impertinence, and disciplines her (Chapter 2).
Later, at lunch, Scout is taking out her frustrations on poor Walter for, as she sees it, getting her in trouble. When she explains what happened to Jem, he immediately understands the situation, and invites Walter to join them for lunch. Walter at first does not know how to respond, and since time is running short, Jem and Scout start out without him. After thinking about it for awhile, Walter decides that since Jem's offer is a neighborly invitation and not charity, it is all right to accept, and he runs after Jem and Scout, calling "Hey, I'm comin'!" (Chapter 3).