QDOS

QDOS may refer to:


 * QDOS (Qasar DOS), the Motorola 6800-based operating system of the Fairlight CMI digital sampling synthesizer series, based on the MDOS (Motorola DOS)
 * Seattle Computer Products QDOS, SCP's Quick and Dirty Operating System in 1980, later renamed to 86-DOS (predecessor of MS-DOS)
 * Sinclair QDOS, the Sinclair QL operating system written in Motorola 68000 assembly language
 * Atari QDOS, the production codename of Disk Operating System 4.0 for Atari 8-bit computers
 * Qdos Entertainment, the UK-based entertainment company who is the world's largest pantomime producer
 * Q:Dos, a recording name for trance musicians Scott Bond, Darren Hodson, John Purser, Nick Rose
 * Qdos, range of no-valve metering pumps
 * QDOS (Quick and Dirty Operating System), first version of the DOS operating system