助听器是听力障碍者使用的辅具，用来补足听力损伤所造成的缺陷。

目前助听器已从传统的模拟式发展至电脑程序化的数字式助听器，可依外型分为下列几类：

A hearing aid or deaf aid is an electroacoustic device which is designed to amplify sound for the wearer, usually with the aim of making speech more intelligible, and to correct impaired hearing as measured by audiometry. In the United States, hearing aids are considered medical devices and are regulated by the Food and Drug Administration (FDA). Ordinary small audio amplifiers or other plain sound reinforcing systems cannot be sold as "hearing aids".