Bullet-resistant glass (also known as ballistic glass, transparent armor, or bulletproof glass) is a material that is especially resistant to penetration by bullets, strong, and optically transparent. Like any other material, it is not completely impenetrable.

It is usually made of a combination of two or more types of glass, one being hard and the other soft. The softer layer makes the glass more elastic, allowing it to flex rather than shatter. The refractive indices of both glasses used in bullet-resistant layers must be nearly identical to maintain transparency and provide an undistorted image through the glass. The thickness of bullet-resistant glass varies between 3/4 and 3 1/2 inches (19 to 89 mm). Bullet-resistant glass is used in windows of buildings that require such security measures, such as jewelers and embassies, as well as military and special vehicles.