GMR is a Polish luthier brand founded in 1987 and based in Bydgoszcz, producing handcrafted custom bass guitars. The shop builds its instruments entirely by hand, without CNC machining, and offers a high degree of customization with long build times typical of small-batch luthiery. A UK-registered arm, GMR Bespoke Bass Guitars, has also been used to serve the British and international market.

The brand is best known for its Bassforce line, available in neck-through (NT) and bolt-on Classic configurations across 4, 5, and 6-string versions. Common specifications include 34-inch scale 24-fret necks, figured maple tops over mahogany bodies, and premium third-party electronics such as Bassculture pickups and John East preamps. GMR positions itself within the boutique bass market alongside other European custom builders, with instruments generally sold direct to order.

GMR has 2 products cataloged on Equipboard, including Boost Effects Pedals and Fuzz Effects Pedals.