The abbreviation DMZ that expands to demilitarized zone can refer to the following concepts:

• In military terminology, a demilitarized zone is an area, usually the frontier or boundary between two or more groups, where military activity is not permitted.
  • See also: Korean Demilitarized Zone
• In computer security terminology, a demilitarized zone is a network area that sits between an organisation's internal network and an external network, usually the Internet.

Other meanings:

• DMZ was also the name of a proto-punk rock and roll band from Boston in the mid-1970s, who later became garage rock revivalists, The Lyres .