Magnús Eiríksson (22 June 1806 – 3 July 1881) was an Icelandic theologian and a contemporary critic of Søren Aabye Kierkegaard (1813–1855) and Hans Lassen Martensen (1808–1884) in Copenhagen.

Due to his very critical attitude towards the church dogma, especially the dogmas of the Trinity of God and the Divinity of Christ, in contrast to which he stressed (at least in his late work) the essential unity of God and the leadership of Jesus (merely) as prophet and teacher, Eiríksson often was labeled as a “pioneer” or “precursor” [1] to the Unitarian movement in Denmark.

Magnús Eiríksson was born the eldest of the five children of Eiríkur Grímsson († 1812), a farmer, and Þorbjörg Stephánsdóttir († 1841), a pastor's daughter, in Skinnalón, Norður-Þingeyjarsýsla, on the northeastern tip of Iceland.

Kierkegaard, however, vigorously protested against this "unauthorized acknowledgment" of his writings by "that raging Roland" and accused Eiríksson of attributing to him motives of which there is not a trace in the book.

[6] Regarding Eiríksson's efforts to get Martensen dismissed, Kierkegaard comments: "And with the violence and force of the Devil he has involved my 'Concluding Unscientific Postscript' in his ... campaign.

But if he has read it, I do know that he has absolutely, mendaciously and presumptuously misunderstood it" [7] In 1850 Eiríksson published pseudonymously [Theophilus Nicolaus] his book Er Troen et Paradox og 'i Kraft af det Absurde'?

German biblical criticism and, in particular, the influence of the Tübingen School caused him to break radically with Johannine and Pauline theology.

In Jøder og Christne [Jews and Christians] (1871) Eiríksson drew the ultimate conclusion and explained that Judaism, which in his terminology meant an immediate childlike trust in God, was the only true religion.

After his death on July 3, 1881, at Frederiks Hospital in Copenhagen, Eiríksson's friends set up a mounted bust on his grave in Garnisons Kirkegård.