Smart glass, also known as switchable glass, dynamic glass, and smart-tinting glass, is a type of glass that can change its reflective properties to prevent sunlight and heat from entering a building and to also provide privacy. Smart glass for building aims to provide more energy-efficient buildings by reducing the amount of solar heat that passes through glass windows.

There are two primary classifications of smart glass: active or passive. The most common active glass technologies used today are electrochromic, liquid crystal, and suspended particle devices (SPD). Thermochromic and photochromic are classified as passive technologies.

When installed in the envelope of buildings, smart glass helps to create climate adaptive building shells, which benefits things such as natural light adjustment, visual comfort, UV and infrared blocking, reduced energy use, thermal comfort, resistance to extreme weather conditions, and privacy. Some smart windows can self-adapt to heat or cool for energy conservation in buildings. Smart windows can eliminate the need for blinds, shades or window treatments.

Some effects can be obtained by laminating smart film or switchable film onto flat surfaces using glass, acrylic or polycarbonate laminates. Some types of smart films can be applied to existing glass windows using either a self-adhesive smart film or special glue. Spray-on methods for applying clear coatings to block heat and conduct electricity are also under development.