OnkartGromt is a Norwegian builder of handmade effects pedals founded by Øyvind Mjanger, with a catalog focused almost entirely on bass guitar. The name combines two words from a western-Norway dialect, roughly translating to "something good." Operating out of Norway as a small workshop, the company designs and assembles its circuits in-house, with Mjanger handling the electronics and Henning Hodne Mjanger contributing on the marketing and music side.

The brand's lineup centers on the Grombass, a bass overdrive/distortion that has gone through multiple revisions including a silicon-carbide variant (Grombass v1.1 SiC) and the v2. Other releases include the Grompressor compressor, the TurboTore parametric EQ/clean boost, the Gromguten germanium distortion, the Tremolando tremolo, and the FunkyFellow envelope filter. The pedals are built around relatively simple, purpose-driven circuits and have developed a niche following among bass players looking for boutique drive and dynamics tools.

Onkart Gromt has 3 products cataloged on Equipboard, including Distortion Effects Pedals, Overdrive Effects Pedals, and Tremolo Effects Pedals. Their gear is featured by 1 artist, with the strongest followings in Rock. Notable users include Nikolai Fraiture.