Oedipus Rex is the classic example of dramatic irony. Dramatic irony occurs when the audience knows something significant that the characters don’t know.
It takes a lot of narrative skill to create effective dramatic irony. Because the audience already knows important information, the focus of the story is on the character instead of a suspenseful plot. It’s more challenging for a storyteller to create characters that readers can empathize with than it is to create an interesting plot.
In the case of Oedipus, the audience already knows that Oedipus is the killer of Laius. Oedipus and the inhabitants of Thebes, however, learn this as the play develops. The audience feels tension as they watch the characters react to each revelation that leads the characters closer to the information that they already have.
Most of the dramatic irony in the play comes from the words of Oedipus himself. For example, early in the play Oedipus says “Whoever among you knows the man who murdered Laius, son of Labdacus, I order him to reveal it all to me.” Here, he is trying to enlist the help of the Thebans in finding Laius’ killer. Of course, we all know that the killer is Oedipus himself.