Elby Designs is an Australian synthesizer company founded in 2003 by Laurie Biddulph and based in Kariong, New South Wales. The brand name is derived from the founder's initials (L.B. — "El-Bee"). The company began as a supplier of DIY kits and PCBs for the synthesizer constructor market, and has grown into a maker of both ready-made modules and complete tabletop instruments.

Elby is best known for its Panther range of Eurorack modules, which makes designs from Ken Stone's Cat Girl Synth (CGS) project available in 3U format, and for its Euro Serge series, a Eurorack-format adaptation of classic Serge modular circuits. The company also produces tabletop synthesizers including the ASM-1 and ASM-2 analog synths, the MonoWave wave-scanning synth (originally designed by Paula Maddox), and the Pixie, a clone of the EDP Wasp. Other offerings include the Construct-A-Rack and Studio Series enclosures, power supplies, and a wide catalog of constructor kits and accessories.

Elby Designs occupies a niche at the intersection of synth-DIY culture and small-batch boutique manufacturing, with a particular focus on preserving and re-issuing influential designs from the broader modular community.

Elby Designs has 7 products cataloged on Equipboard, including Modular Synthesizers. Their gear is featured by 1 artist, with the strongest followings in Electronic. Notable users include Richard Devine.