Ralph Wiggum is a member of Springfield Elementary School. He is best known as the towns resident oddball, and has been immortalized for his non sequiturs and erratic behavior. His lines range from nonsensical, or bizarre interpretations of a current event, to surprisingly profound statements that go over people's heads. For this, Ralph is somewhat of an outcast among his peers, although he seems to be on good terms with a fair number of the other kids at school such as Bart, Lisa, and Milhouse.

The son of Police Chief Clancy and Sarah Wiggum, Ralph is a good-hearted and generally well-meaning boy who suffers from either severe learning and social disabilities, or some other form of childhood psychiatric disorder. The nature of his mentality is kept rather ambiguous, much like many of the signature traits of much of the show's cast. Like almost every other character in Springfield, he may not be quite as simple as he first seems, as evidenced by his hinted immense potential as a performer.