RYO Modular is a Eurorack synthesizer module manufacturer based in Gothenburg, Sweden. Founded by Benjamin and Andreas (with collaborator Tom from the Muffwiggler community) and officially launched in spring 2013, the company takes its name from "Roll Your Own" — a nod to its origins in DIY synth building. RYO releases its modules as PCBs, panels, full DIY kits, and pre-assembled units, and publishes detailed schematics, build guides, and patch ideas for each design.

The company is known for compact, ergonomically focused designs that often lean on unconventional analog circuitry such as vactrol- and LED-based signal paths. Its catalog includes the Optodist vactrol distortion (the brand's debut module), the Aperture vactrol lowpass filter and VCA inspired by the Buchla 200 series, the Penta 5-step sequencer, the VC Sequencer, the 3xVCA, the Amp_MX mixer, and logic and utility modules like (N)AND, (N)OR, X(N)OR, Paths, and Trig_Xpand. RYO's products are distributed alongside Ljunggren Audio, with whom the brand shares a manufacturing and design lineage.

RYO Modular has 15 products cataloged on Equipboard, including Modular Synthesizers. Their gear is featured by 1 artist, with the strongest followings in Electronic and Pop. Notable users include Andrew Huang.