GNOSIS (Great New Operating System In the Sky) is a capability-based operating system that was researched during the 1970s at Tymshare, Inc. It was based on the research of Norman Hardy, Dale E. Jordan, Bill Frantz, Charlie Landau, Jay Jonekait, et al. It provided a foundation for the development of future operating systems such as KeyKOS, EROS, CapROS and Coyotos. After the acquisition of Tymshare, Inc. by McDonnell Douglas in 1984 GNOSIS was sold to Key Logic.

Gnosis is the common Greek noun for knowledge (in the nominative case γνῶσις f.). In Christian, Islamic, or Jewish mysticism, mystery religions and Gnosticism gnosis generally signifies a spiritual knowledge or "religion of knowledge", in the sense of mystical enlightenment or "insight". Gnosis taught a deliverance of man from the constraints of earthly existence through insight into an essential relationship, as soul or spirit, with a place of freedom.