GRP Synthesizer is an Italian maker of analog synthesizers and Eurorack modules, founded by Paolo Groppioni and based in Monte Porzio Catone near Rome. The company is known for fully analog, hand-assembled instruments that draw on classic 1970s synthesizer design language, with an emphasis on discrete circuitry, thru-zero-capable oscillators, and step sequencing integrated into the instrument itself.

The product line centers on the A-series of monophonic and duophonic synthesizers — including the flagship A8, the more compact A4, and smaller A2 and A1 variants — alongside the V22 vocoder, the R24 sequencer/synthesizer, and the Vintage Genesi. GRP also produces a range of Eurorack modules covering VCOs, VCFs, VCAs, ADSRs, LFOs and mixers. Each instrument is built in small runs, with the A8 in particular becoming a collector's item after an initial edition of roughly two dozen units.

The brand's reputation in the analog synth community rests on its boutique, handcrafted approach and on the classic 'big analog' sound of its instruments, which has made it a point of reference for studios and performers looking for high-end Italian-built gear in the tradition of larger modular systems.

Grp Synthesizer has 4 products cataloged on Equipboard, including Modular Synthesizers. Their gear is featured by 5 artists, with the strongest followings in Electronic, Rock, and Metal. Notable users include Jordan Rudess, Jean Michel Jarre, and Vitalic.