Multics was a MainFrame timesharing OperatingSystem designed and implemented at MIT.

Desire for such a system arose from MIT's project MAC to follow its successful CTSS system on the IBM 7094, and so the Multics project began in 1964. It was described in a set of six papers at the 1965 Fall Joint Computer Conference. GE was selected as the hardware vendor and Bell Telephone Laboratories also joined the development team. MIT's research was largely funded by the DARPA.

Multics took longer than planned to become operational, and Bell dropped out of the project in 1969, about the time MIT started offering service to users. Multics continued to evolve and spread to additional sites for the next 16 years as a Honeywell commercial product offering.