Cubase is a MIDI and music sequencer and digital audio editing computer application created by the German firm Steinberg in 1989.

Cubase started as a MIDI recording and editing tool. Later, features for recoding raw audio were introduced. Cubase was originally written for the Atari ST, and has since been ported to Apple Macintosh and Microsoft Windows.

Cubase runs on its own operating system called MROS (MIDI Real-time Operating System) which runs on top of the computer's own operating system. MROS did not initially work well on Windows, which was not intended for real-time applications. This problem has been solved with the increasing CPU speed of the PC.

Almost all versions of Cubase use dongles for copy protection. Problems with the dongles are frequent.

Cubase VST 2.0 in 1999 introduced a virtual instrument interface for software synthesizers. This made it possible for third-party software programmers to create and sell virtual instruments for Cubase. This interface has become a standard for other digital audio editing tools on the Macintosh and Windows platforms.