Acacia Guitars is a boutique custom guitar and bass builder based in Temecula, California. The company was founded by brothers Scott and Greg Lienhard, with Scott serving as the lead designer after studying furniture design and stringed instrument making at Palomar Woodworking School. The shop is family-run, with additional Lienhard brothers Tom and Jack handling CAD/CNC programming and electronics wiring respectively, and David Walston serving as lead shop technician.

The company is known for its headless and ergonomically contoured instrument designs aimed primarily at the progressive rock and metal communities. Their lineup includes models such as the Medusa, the Hades (including the Hades CT and Hades Pro 6), the Romulus series (SN25, ARC, and ARC Carbon Quilt), the Cronus, and the Ares. Each instrument is built to order or in small runs, combining exotic tonewoods with modern hardware and multi-scale/headless configurations.

Acacia's aesthetic emphasizes fluid, organic body shapes and clean headless silhouettes rather than traditional bolt-on designs. The brand positions itself as a small-batch American custom shop, blending hand-woodworking techniques with CNC precision to produce both stock and fully custom instruments.