Nominal religion in Norway is mostly Protestant (Evangelical-Lutheran) with 78.9% of the population belonging to the state Evangelical Lutheran Church of Norway. Early Norwegians, like all of the people of Scandinavia, were adherents of Norse paganism; the Sámi having a shamanisticreligion. Due to the efforts of Christian missionaries, Norway was gradually Christianized in a process starting at approximately 1000 and substantially finished by 1150. Prior to the Reformation, Norwegians were part of the Catholic Church with the conversion to Protestantism commencing in 1536.
In modern times Norway – like many European countries – has seen a great decline in religiosity, at least among non-immigrant Norwegian endemics,and most Norwegians are irreligious: atheism and agnosticism are the most common metaphysical views according to Zuckerman.
Also according to Phil Zuckerman, an Associate Professor of Sociology at Pitzer College, the most recent Norwegian census shows Islam is the third-largest religion due to recent migration trends. Despite the fact that Islam has become the fastest-growing religion throughout many regions of predominantly-Christian and secular Europe since at least the beginning of the 21st century, Norway is currently somewhat of an exception: Christianity is growing fast in Norway due to Christian immigration from Eastern Europe and elsewhere; large numbers of recent immigrants from Poland, Ethiopia and the Philippines have added to the Christian stock of the country in recent years. Nevertheless, Islam is growing quite fast as well as a result of the Church of Norway receiving fewer new members and a growing number of immigrants arriving from the Middle East and other parts of the Muslim world.
Overall, Christian Orthodoxy is the fastest-growing religious tradition in Norway with a rate of 231.1% compared to Islam’s 64.3% from 2000 to 2009. However there are more Muslims in Norway than there are adherents of any specific Christian denomination outside of the Lutheran Church of Norway, with Muslims making up 2.1% of the population as compared to the 0.2% Orthodox Christians, 0.1% Seventh-day Adventists, 0.2% Baptists, etc.
According to the most recent Eurobarometer Poll 2005, 32% of Norwegian citizens responded that “they believe there is a God”. 47% answered that “they believe there is some sort of spirit or life force”. 17% answered that “they do not believe there is any sort of spirit, God, or life force”. 4% answered that they “do not know”.
Zuckerman estimates atheism rates in Norway as ranging from 31 to 72%, based on various studies.
Source: Religion in Norway (Wikipedia; footnotes omitted)