A speaker module adapted to be disposed on a wearable device. The speaker module includes at least one driving unit and an enclosure. The driving unit is configured to produce sound. The enclosure contains the driving unit and has a front chamber and a rear chamber. The front chamber and the rear chamber are individually located at two opposite sides of the driving unit. The enclosure has a front opening, a first rear opening, and a second rear opening. The front opening communicates with the front chamber. The first rear opening and the second rear opening individually communicate with the rear chamber. A sum of sound outputted from the front opening, the first rear opening, and the second rear opening has directivity.