Kz Guitar Works is a handmade electric guitar workshop based in Zushi City, Kanagawa, Japan, founded in 2001 by ESP Craft Academy graduate Kazutaka "Kaz" Ijuin. The shop began as a one-man operation focused on building detailed reproductions of Brian May's homemade "Red Special" guitar, and grew into a small builder offering original designs alongside its Red Special–inspired models.

The lineup centers on several families of instruments, including the Kz One series (Carved Top, Air, RS-Joint bolt-on, and bass variants), the Kz Trad series (ST Trad 22 and TL Trad 22), the Kz RS series of Red Special–style guitars, and models such as the Kz Versa and Astronaut. The workshop also produces its own pickups, tremolo hardware, and pedals, and accepts custom orders through its website and Reverb storefront.

Kz Guitar Works is perhaps best known for its relationship with Brian May of Queen, whose "Super" model built by the shop has served as an official backup to the original Red Special. The builder has also produced signature and custom instruments for members of The Struts, including guitarist Adam Slack (the KzOne Adam Slack and "Adamoo"), bassist Jed Elliott (the "J-Edo" jazz-style bass), and vocalist Luke Spiller (the "Cherry Dandy" acoustic-electric).

KZ Guitar Works has 3 products cataloged on Equipboard, including Solid Body Electric Guitars and Semi-Hollowbody Electric Guitars.