Karl Martin Lönnebo (born 27 February 1930) is a Swedish clergyman who served as Bishop of the diocese of Linköping from 1980 to 1994. Lönnebo was born in in present-day Skellefteå Municipality. He studied theology at Johannelund theological seminary and was ordained within the Swedish Evangelical Mission (Evangeliska Fosterlands-Stitelsen, EFS) in 1954. In 1964 he received a D.Th. degree on his doctoral dissertation Albert Schweitzers etisk-religiösa ideal. He worked as a pastor and chaplain in Uppsala for a number of years, and was appointed Provost (domprost) of Härnösand in 1977. In 1980 he was elected Bishop of Linköping, where he remained until his retirement.