Founded in 1968 by Robert Gallien — a Stanford-educated engineer then working at Hewlett-Packard — Gallien-Krueger is an American manufacturer of bass amplifiers, speaker cabinets, and related gear headquartered in Stockton, California. Originally operating under the name GMT, the company was renamed in the early 1970s when fellow HP engineer Rich Krueger joined as a partner. From the beginning, the company took an unconventional approach, building solid-state amplifiers around transistors rather than the vacuum tubes that dominated the era. Carlos Santana was among the first customers, purchasing a GMT 226A that he famously used at Woodstock in 1969.

The 1982 launch of the 800RB proved to be a defining moment for the brand, establishing Gallien-Krueger as a go-to name in professional bass amplification. The 800RB introduced features like bi-amping and a built-in D.I. that became industry standards, and it remains one of the most recognized bass amp heads ever made. Other innovations include the 400B (the first bass amp with a Contour control), the 200RB (the first rack-mountable instrument amp), and the 2000RB (the first 1000-watt bass head). The MB200, one of the world's smallest and lightest 200-watt bass amplifiers, showcases the brand's continued push toward portable, high-powered designs. The product line spans amp heads (including the RB, Fusion, and Legacy series), Neo and CX speaker cabinets, combo amplifiers, and the Plex bass preamp pedal.

Gallien-Krueger gear has been adopted by bassists across a wide range of genres. Flea of Red Hot Chili Peppers has been a prominent user of GK amplification since the early 1980s, while other notable players include Duff McKagan of Guns N' Roses, Tom Hamilton of Aerosmith, Ted Dwane of Mumford & Sons, and Bryan Beller of The Aristocrats. All products are designed and manufactured in the USA.

Gallien-Krueger has 118 products cataloged on Equipboard, including Bass Amplifier Cabinets, Bass Amplifier Heads, and Bass Combo Amplifiers. Their gear is featured by 168 artists, with the strongest followings in Rock, Electronic, and Pop. Notable users include James Eller, Duff McKagan, and Bryan Beller. Gallien-Krueger's catalog spans the full price spectrum — from entry-level options to high-end flagships.