Islam is the largest religion in Indonesia, with 87.15% of the Indonesian population identifying themselves as Muslims, based on civil registry data in 2025. In terms of population, the country has the world’s largest Muslim population, with an overwhelming 251.25 million people of the country. The Pew Research Center estimated that Sunni comprised approximately ~99% of the country's Muslim population in 2011, with the remaining 1% being Shia, who are concentrated around Jakarta, and about 400,000 Ahmadi as well.
In terms of schools of jurisprudence, based on demographic statistics, 99% of Indonesian Muslims mainly follow the Shafi'i madhhab, smaller numbers follow other schools,Religious clash in Indonesia kills up to six, The Straits Times, 6 February 2011. and the Salafi movement, although when asked, 56% do not adhere to any specific school. The Sunni orders of Sufism are considered essential. Trends of thought within Islam in Indonesia can be broadly categorized into two orientations: "modernism", which closely adheres to orthodox theology while embracing modern learning, and "traditionalism", which tends to follow the interpretations of local religious leaders and religious teachers at Islamic boarding schools (pesantren). There is also a historically important presence of a syncretic form of Islam known as kebatinan, particularly in Java.
Islam in Indonesia is considered to have gradually spread through merchant activities by Arab Muslim traders, adoption by local rulers, and the influence of Sufism since the 12th or the 13th century. During the late colonial era, it was adopted as a rallying banner against colonialism. A 2023 Pew Research Center report gave 93% of the adult Indonesian population identifying themselves as Muslim. Today, although Indonesia has an overwhelming Muslim majority, it is not an Islamic state, but constitutionally a Ketuhanan yang Maha Esa (One Almighty God) state whose government officially recognizes six formal religions.
Distribution
Islam in Indonesia by province and region This is a data table of the percentage of Muslims in Indonesia, provided by the Ministry of Religious Affairs for 2022:
Province Muslim population Total population Muslim percentage Aceh (Highest Percentage of Muslims)5,356,6355,432,312 Bali434,9414,304,574 Bangka Belitung Islands1,344,9031,490,418 Banten11,686,75612,321,660 Bengkulu2,017,8602,065,573 Central Java36,773,44237,783,666 Central Kalimantan2,011,7632,706,950 Central Papua162,7401,348,463 Central Sulawesi2,450,8673,099,717 East Java40,179,56641,311,181 East Kalimantan3,446,6523,941,766 East Nusa Tenggara523,5235,543,239 Gorontalo1,191,4841,215,387 Highland Papua (Lowest Population and Percentage of Muslims)27,3571,459,544 Jakarta9,491,61911,317,271 Jambi3,514,4153,696,044 Lampung8,598,0098,947,458 Maluku997,7241,893,324 North Kalimantan533,675726,989 North Maluku1,005,7271,346,267 North Sulawesi849,2532,666,821 North Sumatra10,244,65515,372,437 Papua320,4421,073,354 Riau5,870,0156,743,099 Riau Islands1,671,2422,133,491 South Kalimantan4,054,0444,178,229 South Papua143,610522,844 South Sulawesi8,359,1669,300,745 South Sumatra8,508,9998,755,074 Southeast Sulawesi2,593,2262,707,061 Southwest Papua230,904604,698 West Java (Highest Population of Muslims)48,029,21549,339,490 West Kalimantan3,320,7195,497,151 West Nusa Tenggara5,361,9205,534,583 West Papua213,230559,361 West Sulawesi1,217,3391,450,610 West Sumatra5,528,4235,664,988 Special Region of Yogyakarta3,433,1293,693,834
RegionMuslim populationTotal populationMuslim %Java149,593,727155,767,102Kalimantan13,366,85317,051,085Lesser Sunda Islands6,320,38415,382,396Maluku Islands2,003,4513,239,591Sumatra52,655,15660,300,894Sulawesi16,661,33520,440,341Western New Guinea1,098,2835,568,264
Denominations
The Islamic schools and branches in Indonesia reflect the activity of Islamic doctrines and organizations operating in Indonesia. In terms of denomination, Indonesia is a majority Sunni country (about 98–99%) with minority of other sects such as Shia Islam and Ahmadiyya. In terms of Islamic schools of jurisprudence, the Shafi'i school is dominant in Indonesia at large; smaller numbers follow other schools (madhhabs),
and the Salafi movement.
Proliferation of the Shafi’i school is considered to be due to Arab merchants from the southern Arabian Peninsula who followed this school of jurisprudence.Randall L. Pouwels (2002), Horn and Crescent: Cultural Change and Traditional Islam, Cambridge University Press, , pp 88–159MN Pearson (2000), The Indian Ocean and the Red Sea, in The History of Islam in Africa (Ed: Nehemia Levtzion, Randall Pouwels), Ohio University Press, , Chapter 2. The Sunni orders of Sufism are considered essential.
Division of Islam in Indonesia
Classical documentations divide Indonesian Muslims between "nominal" Muslims, or abangan, whose lifestyles are more oriented toward non-Islamic cultures, and "orthodox" Muslims or santri, who adhere to the Orthodox Islamic norms. Abangan was considered an indigenous blend of native and Hindu-Buddhist beliefs with Islamic practices sometimes also called Javanism, kejawen, agama Jawa, or kebatinan. On Java, santri was not only referred to a person who was consciously and exclusively Muslim, but it also described persons who had removed themselves from the secular world to concentrate on devotional activities in Islamic schools called pesantren—literally "the place of the santri". The terms and precise nature of this differentiation were in dispute throughout the history, and today it is considered obsolete.
In the contemporary era, distinction is often made between "traditionalism" and "modernism". Traditionalism, exemplified by the civil society organization Nahdlatul Ulama, is known as an ardent advocate of Islam Nusantara, a distinctive brand of Islam that has undergone interaction, contextualization, indigenization, interpretation, and vernacularization in line with socio-cultural conditions in Indonesia. Islam Nusantara promotes moderation, compassion, anti-radicalism, inclusiveness, and tolerance. On the other spectrum is modernism, which is heavily inspired by Islamic Modernism, and the civil society organizations Muhammadiyah and Persis are known ardent proponents. Modernist Muslims advocate for Islamic reform in Indonesia, which is perceived as having deviated from the historical Islamic orthodoxy. They emphasize the authority of the Qur'an and the Hadiths, and oppose syncretism and taqlid to the ulema. This division, however, also has been considered an oversimplification in recent analysis.Von Der Mehden, Fred R. (1995). "Indonesia.". In John L. Esposito. The Oxford Encyclopedia of the Modern Islamic World. Oxford: Oxford University Press.
More recent currents of Islamic thoughts that have taken roots include Islamism. Today, the leading Islamic political party in Indonesia is Prosperous Justice Party (PKS), which is known for serving as a regional wing of Muslim Brotherhood movement in Indonesia.Bruinessen, Martin van, Contemporary Developments in Indonesian Islam Explaining the 'Conservative Turn' . ISEAS Publishing, 2013. Retrieved 2 October 2017. The Islamist Al-Zaytun Islamic Boarding School in West Java is considered the largest pesantren/madrasa in Southeast Asia.
Kebatinan Various other forms and adaptations of Islam are influenced by local cultures that hold different norms and perceptions throughout the archipelago. The principal example is a syncretic form of Islam known as kebatinan, which is an amalgam of animism, Hindu-Buddhist, and Islamic—especially Sufi—beliefs. This loosely organized current of thought and practice was legitimized in the 1945 constitution, and in 1973, when it was recognized as one of the agama, President Suharto counted himself as one of its adherents. The Kebatinan or Kepercayaan has no certain prophet, sacred book, nor distinct religious festivals and rituals; it has more to do with each adherent's internalized transcendental vision and beliefs in their relations with the supreme being. As a result, there is inclusivity in that the kebatinan believer could identify themselves with one of six officially recognized religions, at least in their identity card, and still maintain their kebatinan belief and way of life. Kebatinan is generally characterized as mystical, and some varieties were concerned with spiritual self-control. Although many varieties were circulating in 1992, kebatinan often implies pantheistic worship because it encourages sacrifices and devotions to local and ancestral spirits. These spirits are believed to inhabit natural objects, human beings, artifacts, and grave sites of important wali (Muslim saints). Illness and other misfortunes are traced to such spirits. If sacrifices or pilgrimages fail to placate angry deities, the advice of a dukun or healer is sought. Kebatinan, while it connotes a denial of the militant universalism of orthodox Islam, moves toward a more internalized universalism. In this way, kebatinan moves toward eliminating the distinction between the universal and the local, the communal and the individual.
Other branches
A small minority subscribe to the Shia Islam and Ahmadiyya. Both Shia and Ahmadi Muslims have been facing increasing intolerance and persecutions by reactionary and radical Islamic groups.
Currently, there are approximately 1–3 million Shia Twelvers most of whom are concentrated around Jakarta, also in Java, Sumatra, Madura and Sulawesi islands, and also Ismailis in Bali, which approximates 0.5% or more than 1% of the total Muslim population. The historical Shia community is considered a descendant of the minority segment of Hadhrami immigrants, and it was spread from Aceh, originally a center of Shia Islam in Indonesia. In the contemporary era, interests toward Shia Islam grew after the Iranian Islamic Revolution, since which a number of Shia publications were translated into Indonesian.
Another minority Islamic sect is Ahmadiyya. The Association of Religion Data Archives estimates that, within Jamaah Muslim Ahmadiyah Indonesia (JMAI), there are around 400,000 Ahmadi Muslims in Indonesia, which equates to 0.2% of the total Muslim population, spread over 542 branches across the country. Ahmadiyya history in Indonesia began since the missionary activity during the 1920s established the movement in Tapaktuan, Aceh. A separatist group, Lahore Ahmadiyya Movement for the Propagation of Islam, known as Gerakan Ahmadiyah-Lahore Indonesia (GAI) in Indonesia, has existed in Java since 1924 and had only 708 members in the 1980s.
Organizations
In Indonesia, civil society organizations have historically held distinct and significant weight within the Muslim society. These various institutions have contributed greatly to both the intellectual discourse and public sphere for the culmination of new thoughts and sources for communal movements.Feener, R. Michael. Muslim legal thought in modern Indonesia. Cambridge University Press. Retrieved 3 October 2017. 60% of 200 million Indonesian Muslims identify either as Nahdlatul Ulama or Muhammadiyah, making these organizations a 'steel frame' of Indonesian civil society.Mujani, Saiful and Liddle, R. William. Politics, Islam and Public Opinion. (2004) Journal of Democracy, 15:1, p.109-123.