Eine Atemschutz- Maske (umgangssprachlich Gas- Maske, Atemmaske, im militärischen und Zivilschutzbereich CBRN-Schutzmaske bzw. ABC-Schutzmaske, bei der Nationalen Volksarmee Truppenschutzmaske) ist eine das Gesicht teilweise oder ganz bedeckende Schutzmaske. It serves to protect the wearer from airborne pollutants (respiratory toxins) or pathogens. The various devices are divided into full masks (standardized according to EN 136) and half and quarter masks (EN 140).

Half masks include particle-filtering FFP masks (filtering face piece). Such respiratory protection systems are needed where it is necessary to prevent substances hazardous to health from entering the respiratory tract; for example, in rescue services, fire departments, technical relief organizations, fire investigations, and at workplaces where respiratory toxins (chemical substances, dusts) may occur, e.g., during tank cleaning work.

The respirator can be made of rubber, silicone rubber or a plastic. In the past, leather or fabric, sometimes with rubber coating, were also used. Respirators can be used in conjunction with compressed air breathing systems for self-contained breathing or with respiratory filters for self-contained breathing. In the self-contained version, the respiratory filter can either be attached directly to the mask or connected to it via a hose. Multiple filters or a blower can also be attached for ease. A distinction is made between normal pressure masks and positive pressure masks. Meanwhile, a respirator with integrated data goggles has also been developed to enable navigation in smoke-filled rooms. The system is based on room localization electronics.