Irony occurs when there is a contrast between expectation and reality. Stevenson employs dramatic irony in “The Bottle Imp,” which happens when the reader is aware of information that the characters are not. A key example of dramatic irony occurs when Kokua convinces the old man to take the bottle from Keawe. Keawe is unaware of his wife’s plan, so he maligns the old man and is angry when Kokua defends the man. Due to the interference of the boatswain, who counsels him against trusting women, he even goes as far as to suspect her of infidelity. Readers know that Kokua is actually making a great sacrifice for her husband and this irony builds tension throughout the last act of the story until the truth is revealed to all the characters.

The story’s ending could be read as an example of situational irony, where an expected outcome is changed or subverted. Knowing that the bottle will certainly send someone to hell, readers do not expect any of the characters to willingly purchase it at the lowest possible price of one centime. However, the boatswain eagerly buys it, claiming that he is going to hell anyway.