ADT Security Services, also known as ADT Fire and Security, is a major supplier of electronic security and fire alarm systems, communication systems, and integrated management systems. Established in 1874, it was acquired by Tyco International in 1997, and is headquartered at Boca Raton, Florida. It is one of the major players in the security equipment industry catering to home, small businesses, and medium and large business segments. The company's wide range of electronic surveillance equipment includes home security systems, intruder alarms, public address and voice alarms, access control, and fire alarm systems. ADT has branches across the globe including Europe, Africa, Asia, and Australia.

The ADT Home security system includes an alarm monitoring service that maintains a centralized monitoring station that constantly monitors for any alarm alerts from homes or offices. Whenever an alarm is triggered, the monitoring specialist examines and tries to determine the nature of the alarm response. Accordingly, it informs the police department or any authorized security response service, depending upon the seriousness of the alarm.

Installed in many homes and offices, ADT security systems, such as fire detection alarm and intruder alarms, have helped save numerous lives and property around the world. ADT security devices can be installed in any places that can pose a potential threat to life and property. Apart from the various security devices, there are numerous ADT security signs and warning decals available that can be flagged on prominent locations. These signs and decals can inform others of the presence of surveillance and monitoring systems. They also act as a 'visual deterrent' for potential burglars and provide a first line of defense, besides peace of mind, to the users.