Islam in Malta in the context of Marsa, Malta

Islam is the second-largest religion in Europe after Christianity. Although the majority of Muslim communities in Western Europe formed as a result of immigration, there are centuries-old indigenous European Muslim communities in the Balkans, Caucasus, Crimea, and Volga region. The term "Muslim Europe" is used to refer to the Muslim-majority countries in the Balkans and the Caucasus (Albania, Azerbaijan, Bosnia and Herzegovina, Kosovo, and Turkey) and parts of countries in Central and Eastern Europe with sizable Muslim minorities (Bulgaria, Montenegro, North Macedonia, and some republics of Russia) that constitute large populations of indigenous European Muslims, although the majority are secular.

Islam expanded into the Caucasus through the Muslim conquest of Persia in the 7th century and entered Southern Europe after the Umayyad conquest of Hispania in the 8th–10th centuries; Muslim political entities existed firmly in what is today Spain, Portugal, Sicily, and Malta during the Middle Ages. The Muslim populations in these territories were either converted to Christianity or expelled by the end of the 15th century by the indigenous Christian rulers (see Reconquista). The Ottoman Empire expanded into Southeastern Europe and consolidated its political power by invading and conquering huge portions of the Serbian and Bulgarian empires, and the remaining territories of the region, including the Albanian and Romanian principalities, and the kingdoms of Bosnia, Croatia, and Hungary between the 14th and 16th centuries. Over the centuries, the Ottoman Empire gradually lost its European territories. Islam was particularly influential in the territories of Albania, Bosnia and Herzegovina, and Kosovo, and has remained the dominant religion in these countries.

Islam is the second largest religion in the Netherlands, after Christianity, and is practised by 6% of the population according to 2023. estimates. The majority of Muslims in the Netherlands belong to the Sunni denomination. Many reside in the country's four major cities: Amsterdam, Rotterdam, The Hague and Utrecht.

The early history of Islam in the Netherlands can be traced back to the 16th century, when a small number of Ottoman merchants began settling in the nation's port cities. As a result, improvised mosques were first built in Amsterdam in the early 17th century. In the ensuing centuries, the Netherlands experienced sporadic Muslim immigration from the Dutch East Indies, during their long history as part of the Dutch overseas possessions. From the dissolution of the Ottoman Empire after the First World War until the independence of Indonesia, the Dutch East Indies contained the world's second largest Muslim population, after British India. However, the number of Muslims in the European territory of the Kingdom of the Netherlands was very low, accounting for less than 0.1% of the population.

Islam is the most popular religion in Bosnia and Herzegovina. It was introduced to the local population in the 15th and 16th centuries as a result of the Ottoman conquest of Bosnia and Herzegovina.

Muslims make the largest religious community in Bosnia and Herzegovina at around 51% of the population.

Islam in Montenegro refers to adherents, communities and religious institutions of Islam in Montenegro. It is the second largest religion in the country, after Christianity. According to the 2011 census, Montenegro's 118,477 Muslims make up 19.11% of the total population. Montenegro's Muslims belong mostly to the Sunni branch. In 2023, Montenegro's 124,668 Muslims made up 19.99% of the total population.

Islam in Georgia (Georgian: ისლამი საქართველოში, romanized: islami sakartveloshi) was introduced in 654 when an army sent by the Third Caliph of Islam, Uthman, conquered Eastern Georgia and established Muslim rule in Tbilisi. Currently, Muslims constitute approximately 9.9% of the Georgian population. According to other sources, Muslims constitute 10-11% of Georgia's population.

In July 2011, the Parliament of Georgia passed new law allowing religious minority groups with "historic ties to Georgia" to register. The draft of the law specifically mentions Islam and four other religious communities.

Islam is a major religious minority in the Russian Federation, which has the largest Muslim population in Europe. According to the US Federal Research Division 1998 reference book, Muslims in Russia numbered about 19% of the religious population.

Recognized under the law and by Russian political leaders as one of Russia's traditional religions, Islam is a part of Russian historical heritage, and is subsidized by the Russian government. The position of Islam as a major Russian religion, alongside Orthodox Christianity, dates from the time of Catherine the Great, who sponsored Islamic clerics and scholarship through the Orenburg Assembly.

Islam arrived in Albania mainly during the Ottoman period when the majority of Albanians over time converted to Islam under Ottoman rule. Following the Albanian National Awakening (Rilindja) tenets and the de-emphasis of religious tradition in Albania, all governments in the 20th century pursued a secularization policy, most aggressively under the People's Socialist Republic of Albania, which actively persecuted Muslims. Due to this policy, Islam, as with all other faiths in the country, underwent radical changes. Decades of state atheism, which ended in 1991, brought a decline in the religious practice of all traditions. The post-communist period and the lifting of legal and other government restrictions on religion allowed Islam to revive through institutions that generated new infrastructure, literature, educational facilities, international transnational links and other social activities.

According to the 2023 census, Islam is the largest religion, with a 50.67% majority of Albanians identifying as Muslim, including 1,101,718 (45.86%) Sunni Muslims, and 115,644 (4.81%) Bektashi Muslims.

Islam in Kosovo has a long-standing tradition dating back to the Ottoman conquest of the Balkans. Before the Battle of Kosovo in 1389, the entire Balkan region had been Christianized by both the Western and Eastern Roman Empire. From 1389 until 1912, Kosovo was officially governed by the Muslim Ottoman Empire and a high level of Islamization occurred among Catholic and Orthodox Albanians, mainly due to Sufi orders and socio-political opportunism. Both Christian and Muslim Albanians intermarried and some lived as "Laramans", also known as Crypto-Christians. During the time period after World War II, Kosovo was ruled by secular socialist authorities in the Socialist Federal Republic of Yugoslavia (SFRY). During that period, Kosovars became increasingly secularized. After the end of the communist period, religion had a revival in Kosovo. Today, 95.6% of Kosovo's population are Sunni Muslims, most of whom are ethnic Albanians. There are also non-Albanian speaking Muslims, who define themselves as Bosniaks, Gorani and Turks.

Islam in Kosovo is predominantly Hanafi Sunni, the most widespread tradition in the Balkans. Additionally, Kosovo has Sufi orders, particularly the Bektashi order, which blends elements of Shia and Sufi traditions. Other Sufi brotherhoods, such as the Halveti and Kadiri orders, also exist. According to a 2012 study by the Pew Research Center, 58% of muslims in Kosovo are non-denominational Muslims, which is practicing Islam without strict adherence to a particular sect or school of thought.

Islam is the majority religion in Azerbaijan, with various reports have estimated that 97.3% (CIA, 2020) or 99.2% (Pew Research Center, 2006) of the population identify as Muslim, with the majority (50–65%) being Shias and a significant minority (35–40%) being Sunnis. Traditionally, the differences between these two branches of Islam have not been sharply defined in Azerbaijan, as a major portion of the population are cultural Muslims. As such, the country is considered to be the most secular in the Muslim world.

Shia Muslims in the country typically adhere to the Ja'fari school of Shia Islam, while most Sunni Muslims follow the Hanafi school. Due to many decades of Soviet atheist policy, religious affiliation in Azerbaijan is often nominal, and Muslim identity tends to be based more on culture and ethnicity than on religion. Shia Islam is prevalent in the western, central, and southern regions of the country. Traditionally, villages around Baku and the Lankaran region are considered Shia strongholds. In contrast, Sunni Islam is dominant in the northern regions.

Islam is the second-largest religion in France after Christianity. As of the most recent estimates, it is followed by approximately 10% of the population aged 18-59 in 2019-2020—according to data from INSEE.

The majority of Muslims in France belong to the Sunni denomination and are of foreign origins. Sizeable minorities of Shia and non-denominational Muslims also exist. The French overseas region of Mayotte has a majority Muslim population, with 97% of the population following Islam.

Abu'l-Abbas Muhammad I ibn al-Aghlab (Arabic: أبو العباس محمد الأول بن الأغلب) (died 856) was the fifth emir of the Aghlabid dynasty, who ruled over Ifriqiya, Malta, and most of Sicily from 841 until his death. He also led the raid of Rome.

Muhammad I was the son of the dynasty's fourth emir, Abu Iqal (838–841). Muhammad I turned out to be a great commander and economic strategist, like his uncle Ziyadat Allah I of Ifriqiya and his rival Asad ibn al-Furat. Under his reign, the Aghlabids continued their expansion into the Mediterranean, conquering Messina, Taranto, large parts of Apulia and supporting Emir Kalfün with the establishment of an Islamic Bari.

Spain is a Christian majority country, with Islam being a minority religion, practised mostly by immigrants from Muslim majority countries, and their descendants.

Islam was a major religion on the Iberian Peninsula, beginning with the Muslim conquest of the Iberian Peninsula and ending (at least overtly) with its prohibition by the modern Spanish state in the mid-16th century and the expulsion of the Moriscos in the early 17th century, an ethnic and religious minority of around 500,000 people. Although a significant proportion of the Moriscos returned to Spain, or avoided expulsion, the practice of Islam had faded into obscurity by the 19th century.

Muslims in North Macedonia represent just under one-third of the nation's total population according to the 2021 census, making Islam the second most widely professed religion in the country. Muslims in North Macedonia follow Sunni Islam of the Hanafi madhhab. Some northwestern and western regions of the country have Muslim majorities. A large majority of all the Muslims in the country are ethnic Albanians, with the rest being primarily Turks, Romani, Bosniaks or Torbeš.

Islam in Austria is the largest minority religion in the country, practiced by 8.3% of the total population in 2021 according to the Statistics Austria. The majority of Muslims in Austria belong to the Sunni denomination. The first Muslims came to Austria during the 1960s as migrant workers from Turkey and Yugoslavia. There are communities of Arab and Afghan origin as well.

Islam in Bulgaria is a minority religion and the second largest religion in the country after Christianity. According to the 2021 Census, the total number of Muslims in Bulgaria stood at 638,708 corresponding to 9.8% of the population. Ethnically, Muslims in Bulgaria are Turks, Bulgarians and Roma, living mainly in parts of northeastern Bulgaria (mainly in Razgrad, Targovishte, Shumen and Silistra Provinces) and in the Rhodope Mountains (mainly in Kardzhali Province and Smolyan Province).

Swedish contact with the Muslim world dates back to the 7th–10th centuries, when the Vikings traded with Muslims during the Islamic Golden Age. Since the late 1960s and more recently, Muslim immigration from the Middle East, Balkans and Horn of Africa has impacted the demographics of religion in Sweden, and has been the main driver of the spread of Islam in the country. Islam in Sweden increased at most as a result of high refugee influxes, notably during the Yugoslav Wars and the Somali Civil War in the 1990s, Iraq War in the 2000s and Syrian civil war in the 2010s.

The Muslim community in Sweden hails from numerous countries, making it a complex and heterogeneous population. According to a 2019 report from the Swedish Agency for Support to Faith Communities, there were 200,445 Muslims in Sweden who practiced their religion regularly; this count came from those registered with Islamic congregations. The US Department of State's Sweden 2014 International Religious Freedom Report set the 2014 figure of Muslims in Sweden at around 600,000 people, 6% of the total Swedish population. There are no official statistics on how the Swedish population identifies religiously, so it is not possible to know how many people actually identify as Muslims. Estimates suggest that around 8% of the population—approximately 800,000 people—have a Muslim background in Sweden as of 2017. However, this figure has not been verified, and the source, the Pew Research Center (an American think tank), has been shown to be inaccurate in the past.

Islam is the second-largest religion in Belgium, after Christianity. The exact number of Muslims in Belgium is unknown but various sources estimate that 4.0% to 7.6% of the country's population adheres to Islam. The first registered presence of Islam in Belgium was in 1829, but most Belgian Muslims are first-, second-, or third-generation immigrants that arrived after the 1960s.

Islam's significance in Germany increased after the labour migration in the 1960s and several waves of political refugees since the 1970s. In2019, there were 5.3–5.6 million Muslims with a migrant background in Germany (6.4–6.7% of the population), in addition to Muslims who do not fit into that category. A similar survey in 2016 estimated a number of 4.4–4.7 million Muslims with a migrant background (5.4–5.7% of the population) at that time. A survey in 2009 estimated a total number of up to 4.3 million Muslims in Germany. There are also higher estimates: according to the German Islam Conference, Muslims represented 7% of the population in Germany in 2012.

In 2014, it was estimated that 20,000-100,000 Germans converted to Islam, numbers comparable to those in France and in the United Kingdom.

Islam is the second most practiced religion in Liechtenstein after Christianity.

Islam in Switzerland has mostly arrived via immigration since the late second millennium. Numbering below 1% of total population in 1980, the fraction of Muslims in the population of permanent residents in Switzerland has quintupled in thirty years, estimated at just above 5% as of 2013. The Turks and those from The Balkans (Bosnia-Herzegovina and Albania) make up the largest group. There is also a large North African community (most of them are from Tunisia and Morocco) and a significant Middle Eastern community. This is because, in the 1960s and 1970s, Switzerland encouraged young men from Yugoslavia and Turkey to come as guest workers. Initially these young men were only planning on staying in Switzerland temporarily, however, revised Swiss immigration laws in the 1970s permitted family regrouping. Consequently, these men ended up staying in Switzerland as these new laws allowed the wives and children of these young men into the country. Since this time period, most of the Muslim immigration to Switzerland stems from asylum seekers arriving primarily from Eastern Europe. In more recent years, there has been migration from Turkey, the Balkans (mainly Albania, Kosovo and Bosnia and Herzegovina), Iraq, Syria, Morocco, Somalia, and Tunisia.

The vast majority of Muslims in Switzerland adhere to the Sunni Islam branch. Notable Swiss Muslims include Tariq Ramadan, Frithjof Schuon, Titus Burckhardt, Granit Xhaka, Xherdan Shaqiri and Isabelle Eberhardt.