GEOS

GEOS may refer to:

Computer software

 * GEOS (8-bit operating system), an operating system originally designed for the Commodore 64
 * GEOS (16-bit operating system), a DOS-based graphical user interface and x86 operating system
 * GEOS (securities processing software), an integrated online system for the management and processing of securities
 * GEOS (software library), an open-source geometry engine
 * Goddard Earth Observing System, an Earth system model

Other

 * GEOS (eikaiwa), an English conversation teaching company based in Japan
 * GEOS circle, an intersection of four lines that are associated with a generalized triangle
 * GEOS (satellite), a research satellite from ESRO (1978–1982)
 * GEOS (satellite series), three research satellites from NASA
 * Groupe GEOS, a French business consultancy