Yemen war explained: who is fighting and why

A guide to the movements, governments and outside powers involved in Yemen's conflict, and how a decade-old civil war became a multi-front regional crisis.

Key terms

Head of State / Head of Government
In Yemen's political system, the president serves as head of state, while a prime minister runs the daily cabinet, the government.

Houthis
Officially called Ansar Allah, the movement was formed in northern Yemen by the al-Houthi family in the 1990s. Rooted in Zaidi Islam, it is backed by Iran.

Imamate
In Sunni Islam, the term refers to general political and communal leadership of the Muslim community. In Shia Islam, it is a core belief that specific, divinely appointed leaders succeed the Prophet Muhammad to guide the community in both spiritual and worldly matters.

Internationally Recognized Government (IRG)
The broad umbrella term used by the United Nations, foreign governments and media for the legal state authority of the Republic of Yemen. It holds Yemen's seat at the UN, its foreign embassies, and its official status under international law.

Marxism-Leninism
A communist political ideology developed by Vladimir Lenin, merging Karl Marx's economic and historical theories with Lenin's own political tactics and additions, such as the vanguard party and the theory of imperialism.

Presidential Leadership Council (PLC)
The eight-member ruling executive body that runs the IRG.

Southern Transitional Council (STC)
A political and paramilitary organization that advocates for the secession of South Yemen, seeking to reverse the 1990 unification and restore the independent southern state that existed before it.

Zaidi Shia (or Zaydism)
One of the three main branches of Shia Islam, alongside Twelverism and Ismailism. Named for Zayd ibn Ali, the great-grandson of Ali ibn Abi Talib, Zaidis are sometimes called "Fivers" because they recognize Zayd as the fifth Imam. They live primarily in northwestern Yemen and parts of Saudi Arabia.

How Yemen got here

1962
North Yemen (Yemen Arab Republic)
A military coup against the royalist Imamate sparked an eight-year civil war between republicans, backed by Egypt, and royalists, backed by Saudi Arabia. Ali Abdullah Saleh took power in the north in 1978.
South Yemen (People's Democratic Republic of Yemen)
Britain withdrew from Aden in 1967, and the south became the Arab world's only Marxist-Leninist state, tied to the Soviet Union. A brief, bloody internal civil war tore through the southern regime in 1986.

1990–2010
Unification and its first crisis
North and South Yemen merged peacefully on May 22, 1990, under Ali Abdullah Saleh as president. Deepening political rifts caused a short civil war in 1994 when southern leaders tried to secede; Saleh's northern forces won, cementing central control. Between 2004 and 2010, the government fought a series of intermittent, brutal conflicts against Houthi insurgents in the northern province of Saada.

2011–2015
Arab Spring to Houthi takeover
Mass protests erupted in 2011 against Saleh's long rule. In February 2012, Saleh was forced to step down; his vice-president, Abdrabbuh Mansur Hadi, became president, with Mohammed Basindawa as prime minister, as part of a transitional government backed by Gulf Arab monarchies led by Saudi Arabia, alongside Western support.
The Houthi movement then allied with the deposed Saleh and seized the capital, Sanaa, in late 2014 and early 2015, forcing the Internationally Recognized Government to flee. A Saudi-led military coalition intervened in March 2015 to defeat the Houthis and restore the government, triggering a humanitarian crisis and a prolonged stalemate that has lasted more than a decade.

2022
A split leadership
In April 2022, Hadi, who had remained the internationally recognized president for a decade, officially resigned and transferred his powers to the Presidential Leadership Council, a body designed to unite the various factions opposing the Houthis. The Houthi movement in Sanaa rejects the PLC and runs a rival body, the Supreme Political Council, whose chairman, Mahdi al-Mashat, claims the title of president. His authority is recognized only by Iran.

Present day

Who controls what
Ground fighting inside Yemen today is mostly the Houthis versus the Internationally Recognized Government and the Southern Transitional Council. A second, separate front has also opened in the south: the IRG and the UAE-backed STC, nominal allies against the Houthis, have fought each other over control of southern territory, including a government operation that recaptured the STC's de facto capital, Aden, in January 2026.

Why the Houthis target Saudi Arabia, not just Yemen's front lines
Saudi Arabia has generally kept its own ground troops out of Yemen, relying instead on air power, intelligence and logistics support for Yemeni anti-Houthi forces rather than large troop deployments inside the country. That leaves the Houthis with little Saudi ground presence to fight directly, so their pressure on the kingdom takes a different form: strikes on Saudi oil infrastructure and tankers, and a declared blockade of shipping to Saudi ports.
This is a deliberate asymmetric strategy. A much weaker military cannot win a conventional fight, so it targets the stronger side's economic lifelines and politically sensitive assets instead, forcing Saudi Arabia to divert significant military resources to defense even though the large majority of drones and missiles are intercepted. The Houthis also frame these strikes as direct retaliation, arguing that if Saudi Arabia can strike Yemen from outside its borders, they are entitled to strike back the same way; they have tied an end to their blockade to demands including Saudi Arabia lifting what they call its own blockade of Yemen. Some of this activity also reflects the Houthis' alignment with Iran's wider regional network, using shipping disruption as leverage connected to the broader conflicts involving Israel and Iran, not purely Yemen-specific calculation.

A deepening humanitarian crisis
Beyond the fighting, Yemen remains one of the world's most severe humanitarian emergencies. More than 22 million people, over half the population, are projected to need humanitarian assistance in 2026, with millions internally displaced and facing acute food insecurity. UN officials have described the health system as collapsing under the strain of continued conflict and underfunded relief efforts.