Mike Lull Custom Guitars is a Bellevue, Washington-based builder of handmade electric basses and guitars, with a reputation built first on repair and setup work before expanding into full instrument manufacturing. Mike Lull began repairing guitars as a teenager in 1970 and opened Mike Lull's Guitar Works in 1976, earning a following among Pacific Northwest players for his fretwork and setups. The custom bass and guitar lines launched in 1995, and the shop has continued to operate as a family business out of its Bellevue location.

The company is best known for its basses, which take cues from classic Fender-style designs while adding modern refinements in playability and tone. The bass catalog includes P-style and J-style models (P4/P5, PJ4/PJ5, JT4/JT5), V-body models (V4/V5), the M-series (M4/M5 and M4V/M5V), and short-scale offerings like the P430 and J430. Signature models include the IMA4 and TPT4. Mike Lull also builds electric guitars and offers Heirloom Editions with nitrocellulose aging, custom orders, and PLEK-based fretwork services.

Over the decades the shop has built or serviced instruments for a wide range of artists spanning Seattle rock, session work, and touring bands, with clientele that has included members of Heart, Queensrÿche, Pearl Jam, Soundgarden, Foo Fighters, and Death Cab for Cutie, among others.

Mike Lull has 9 products cataloged on Equipboard, including Electric Basses and Semi-Hollowbody Electric Guitars. Their gear is featured by 12 artists, with the strongest followings in Rock, Jazz, and Pop. Notable users include Bryan Beller, Ian Martin Allison, and Stu Cook.