Steve Morrell Custom is the maker's mark associated with a small number of one-off bass guitars built by luthier Steve Morrell (also spelled Morell on instrument hardware). The shop is not a production brand and has no commercial catalog of stock models.

The most documented example is a teal precision-style bass labeled "Steve Morell Custom 001" on the headstock, with "Custom built for Cliff Williams" inscribed on the rear. The instrument features a 21-fret ebony fretboard with eight mother-of-pearl phallic inlays, three EMG pickups, a single-ply pickguard, single volume control, a Hipshot D-tuner, and a matching teal headstock. AC/DC bassist Cliff Williams was photographed playing the bass in the mid-1980s, and an image of him with the instrument appeared on the cover of the songbook Play Bass With… The Best of AC/DC.

Steve Morrell Custom has 2 products cataloged on Equipboard, including Electric Basses. Their gear is featured by 1 artist, with the strongest followings in Rock and Pop. Notable users include Cliff Williams.