A speaker assembly has a mounting box and a speaker. The mounting box has one bottom plate, a first sidewall, a second sidewall, and a third sidewall. The speaker is mounted on the mounting box. The third sidewall is between the first sidewall and the second sidewall, and the speaker and the three sidewalls define an opening. A display device has a casing, a backlight module and the aforementioned speaker assembly. The backlight module is in the casing, and the speaker assembly is located in a space defined by the casing and the backlight module.