Reactable is an electronic musical instrument developed at the Music Technology Group of Universitat Pompeu Fabra in Barcelona, Spain by Sergi Jordà, Marcos Alonso, Martin Kaltenbrunner, and Günter Geiger. First publicly presented in 2005, it consists of a round translucent table that functions as a tangible user interface for a virtual modular synthesizer. Performers place physical blocks called "tangibles" on the backlit surface and manipulate them — along with finger gestures on the display — to patch oscillators, filters, sequencers, and effects in real time, with the resulting signal flow visualized as glowing connections between objects.

Reactable Systems was founded in 2009 to commercialize the instrument, producing the full-size Reactable Experience aimed at installations and museums, and the more portable Reactable Live geared toward DJs and electronic performers. The company also released Reactable Mobile, a touchscreen adaptation of the instrument for iOS and Android, along with related apps including ROTOR, STEPS, and SNAP.

The Reactable drew widespread attention after Björk integrated it into her live setup for the 2007 Volta world tour, debuting it at Coachella and continuing to use it on the Biophilia tour. Rolling Stone described it as a standout instrument of 2007, and it has since been cited as a landmark example of tangible interface design in electronic music.

Reactable has 3 products cataloged on Equipboard, including Sound Modules. Their gear is featured by 3 artists, with the strongest followings in Rock, Pop, and Electronic. Notable users include Björk, Armin Van Buuren, and Will Champion.