Karl Green (born Karl Anthony Green on 31 July 1947, at Park Hospital, Davyhulme) is an English songwriter, musician and bassist who was the bass guitarist and backing singer for the 1960s British band Herman's Hermits, which featured Peter Noone. Green co-wrote a number of songs for the band, and was a capable player but was replaced by session players on some of Herman's Hermits mid-career singles. Green nevertheless played on many Herman's Hermits recordings. Green was in Herman's Hermits from its creation until 1980, when he left to pursue a life outside of music.
On VH1's My Generation: Herman's Hermits episode he speaks fondly of his early days with Noone, and of his admiration for their guitarist Derek "Lek" Leckenby.
As of 2014[update], Green has begun performing live concerts once again. His band includes longtime professional musicians Bob Abrams, Mike Bruccoleri, and Gina Knight.