Jóhannes Gunnarsson, SMM (3 August 1897—17 June 1972) was an Icelandic prelate of the Roman Catholic Church.

His grandfather was a leader in the Althing, and his father converted to Roman Catholicism while attending school in Denmark; he was Iceland's only native Catholic for 20 years.

On 23 February 1943 Jóhannes was appointed Apostolic Vicar of Iceland and titular bishop of Hólar by Pope Pius XI.

He received his episcopal consecration on the following 7 July at St. Patrick's Catholic Church in Washington, D.C.[2] He was enthroned as apostolic vicar after returning to Iceland, where he was the first native bishop in nearly four centuries; the last was Jón Arason, who was beheaded with his two sons by King Christian III in 1550.

Jóhannes attended the Second Vatican Council from 1962 to 1965, and resigned his post in 1967, after 25 years of service, before dying at the age of 74.