• Open system (computing), one of a class of computers and associated software that provides some combination of interoperability, portability and open software standards, particularly Unix and Unix-like systems
• Open system (systems theory), a system where matter or energy can flow into and/or out of the system, in contrast to a closed system, where energy can enter or leave but matter may not
• Open system, in management science a system that is capable of self-maintenance on the basis of throughput of resources from the environment

See also

• Open circuit