The Korg OASYS is a workstation synthesizer released in 2005 using a custom Linux operating system that was designed to be arbitrarily expandable via software updates, with its functionality limited only by the PC-like hardware.

OASYS was a software implementation of the research project that ultimately resulted in the OASYS PCI, a DSP card which offered multiple synthesis engines. The original OASYS keyboard concept had to be scrapped because of too high production cost and limitations of then-current technology.

Production of the OASYS was officially discontinued in April 2009. Korg sold just over 3000 units worldwide. The final software update was released on November 24, 2009.