Geiss is the design name behind a small line of electronic musical instruments created by Michel Geiss, a French sound engineer, technician, and musician best known for his decades-long collaboration with Jean-Michel Jarre. Geiss-designed instruments are custom-built electronic sequencers and rhythm devices, most famously the Matrisequencer 250 — a matrix step sequencer he developed in 1978 during the recording of Jarre's Equinoxe and later used on Rendez-Vous (1986).

The Matrisequencer was followed by the Digisequencer, developed in 1992 by a team led by Geiss for use on Jarre's Chronologie album, and a custom drum machine called the RhythmiComputer. The instruments are characterized by their grid-based, hands-on programming interfaces aimed at intuitive pattern creation and live manipulation rather than menu-driven workflows.

Geiss instruments have always been built in very small quantities and are closely associated with the French electronic music scene that grew up around Jarre. Beyond his work with Jarre, Michel Geiss has also worked as an engineer with French artists including Marc Lavoine, Patrick Bruel, and Laurent Voulzy.

Geiss has 2 products cataloged on Equipboard, including Drum Machines and Synthesizers. Their gear is featured by 1 artist, with the strongest followings in Electronic. Notable users include Jean Michel Jarre.