The historical division between Sunni and Shi‘a Islam has profoundly influenced Middle Eastern politics, social structures, conflicts and alliances, shaping the modern Arab states and their governance.

Origins of the Sunni–Shi‘a Divide

The split between Sunni and Shi‘a Muslims stems from a seventh-century dispute over leadership succession following the death of the Prophet Muhammad in 632 CE.

This schism became institutionalised over centuries, evolving into distinct religious doctrines, legal schools, rituals and political outlooks. Sunni Islam became dominant across most of the Islamic world, while Shi‘a Islam developed strongholds particularly in Persia (modern Iran) and parts of the Arab world.

Demographic Patterns and Geographic Distribution

Sunni Muslims comprise roughly 85–90% of the global Muslim population, while Shi‘a Muslims make up 10–15%, concentrated in:

• Iraq – significant Shi‘a majority but historically ruled by Sunni elites until 2003.

• Lebanon – large Shi‘a population represented by groups like Hezbollah.

• Bahrain – Shi‘a majority under a Sunni monarchy.

• Saudi Arabia – Shi‘a minority mainly in the oil-rich Eastern Province.

• Yemen – divided between Sunni Shafi‘i and Shi‘a Zaydi communities.

These demographics have shaped state structures, political power dynamics and sectarian relations throughout the Arab world.

Political Power and Sectarian Hierarchies

Sunni Dominance and State Formation

Most Arab states emerged under Sunni leadership, reflecting both demographic majorities and the historical dominance of Sunni caliphal traditions. Monarchies like Jordan and Saudi Arabia and republics such as Egypt and Syria (before the Baathist era) were built upon Sunni political and religious legitimacy.

Key features included:

• State-sponsored Sunni religious institutions (e.g., Al-Azhar in Egypt).

• Use of Sunni jurisprudence (Sharia schools) as the basis for legal systems.

• Marginalisation or suppression of Shi‘a groups to prevent political dissent.

Shi‘a Marginalisation and Resistance

In several states, Shi‘a communities faced discrimination, exclusion from political power, and restrictions on religious practice. This often provoked sectarian resistance movements and calls for reform or autonomy, as seen in:

• Iraq under Saddam Hussein, where Shi‘a were politically excluded despite being the majority.

• Saudi Arabia, where Shi‘a activism in the Eastern Province challenged state authority, particularly during the 1979 Islamic Revolution in neighbouring Iran.

• Bahrain, where Shi‘a protests against Sunni rule culminated in significant unrest during the Arab Spring of 2011.

Revolutionary Change and Shifting Power Balances

The 1979 Iranian Revolution transformed the sectarian landscape of the Middle East. It established a Shi‘a theocracy under Ayatollah Khomeini, promoting the idea of wilayat al-faqih (guardianship of the jurist), which challenged Sunni monarchies and secular regimes.

This revolution inspired Shi‘a movements across the Arab world:

• Formation of Hezbollah in Lebanon (1982), blending religious ideology with political militancy.

• Shi‘a uprisings in Iraq (1991) and Bahrain (1990s).

• Heightened sectarian rivalry in the Iran–Iraq War (1980–1988), where Sunni-led Iraq sought to contain Shi‘a revolutionary influence.

Sectarianism in Modern Conflicts

Sectarian identities have often been manipulated by state and non-state actors to justify policies, mobilise support, or delegitimise rivals. Key examples include:

Iraq Post-2003

The US-led invasion toppled Saddam Hussein and shifted power to the Shi‘a majority, leading to:

• A Shi‘a-dominated government, provoking Sunni insurgencies and sectarian violence.

• Emergence of extremist groups like al-Qaeda in Iraq and later ISIS, which framed their struggle as defence against Shi‘a dominance.

• Persistent divisions in politics, security forces, and society.

Syria’s Civil War (2011–)

The conflict deepened Sunni–Shi‘a polarisation:

• The Alawite-led Assad regime (an offshoot of Shi‘a Islam) retained power with Iranian and Hezbollah support.

• Sunni opposition forces, backed by Gulf states and Turkey, sought regime change.

• The war became a proxy battlefield for broader Sunni–Shi‘a and Saudi–Iranian rivalries.

Yemen’s Conflict

Sectarian dynamics underpin the war between:

• Sunni-led government forces backed by Saudi Arabia.

• Shi‘a Zaydi Houthi rebels supported by Iran.
  The conflict illustrates how sectarian identity intertwines with political, tribal and regional disputes.

Religion, Society and Identity

Sectarianism and Social Structures

Sunni and Shi‘a identities shape not only political alignments but also education, law, and social networks. Religious festivals such as Ashura (commemorating Imam Husayn’s martyrdom) are vital to Shi‘a communal identity, while Sunni religious institutions reinforce orthodox interpretations and state legitimacy.

A high-resolution aerial view of pilgrims in Karbala commemorating Ashura, illustrating the scale and communal importance of Shi‘a ritual identity in the Arab world. Source

Cross-Sectarian Cooperation

Despite tensions, there have been instances of cooperation:

• Sunni and Shi‘a groups have united against colonial powers, as during the Iraqi revolt of 1920.

• Cross-sectarian coalitions formed in Lebanon’s political system, though often fragile and contested.

• In some states like Oman, sectarian divisions are less politically significant, demonstrating that identity’s impact varies by context.

The Saudi–Iranian Rivalry and Its Sectarian Dimensions

The geopolitical rivalry between Sunni-majority Saudi Arabia and Shi‘a-majority Iran underpins much of the region’s sectarian polarisation. Each state claims leadership of the Islamic world:

• Saudi Arabia projects itself as the guardian of Sunni orthodoxy and the Two Holy Mosques.

• Iran promotes Shi‘a revolutionary ideology and support for Shi‘a movements abroad.

This rivalry manifests in proxy conflicts, media narratives and diplomatic alignments, entrenching sectarian identities as tools of statecraft and ideological competition.

Sectarianism and the Arab Spring

The 2011 uprisings reshaped sectarian politics:

• Bahrain’s Shi‘a protests were crushed with Saudi assistance, highlighting Sunni fears of Iranian influence.

A high-resolution photograph of Pearl Roundabout during Bahrain’s 2011 protests, showing Shi‘a-led demonstrations against Sunni monarchy and illustrating sectarian dimensions of the Arab Spring. Source

• Iraq’s Sunni protests (2012–2013) expressed resentment toward Shi‘a-dominated governance.

• Syria’s conflict deepened sectarian divides across the region.

These events show how demands for democracy and reform became intertwined with long-standing sectarian grievances.

Legacy and Continuing Influence

The Sunni–Shi‘a divide continues to shape political legitimacy, alliances, identity, and conflict in Arab states. While deeply rooted in theological differences, it is often politicised and instrumentalised in pursuit of power, shaping the trajectory of the modern Middle East and its complex state and societal dynamics.