The Syrian civil war (2011–2024) involved a number of states and armed groups. The main belligerents were Ba'athist Syria and allies, the Syrian opposition and allies, Al-Qaeda and affiliates, the Islamic State, and the Kurdish-led Syrian Democratic Forces.

Syrian government (Ba'athist regime) and allies

A number of sources have emphasized that as of at least late-2015/early-2016 the Assad regime was dependent on a mix of volunteers and militias, rather than the regular Syrian Armed Forces. Between 2016 and 2020, with the help of Russia and Iran, the Syrian Arab Armed Forces were rebuilt and had united most of the armed militias.

Syrian Armed Forces

The Syrian Armed Forces were made up of the Syrian Arab Army (including Republican Guard), Syrian Arab Navy, Syrian Arab Air Force, the Syrian Air Defense Force and the paramilitary National Defence Forces. Before the uprising and war broke out, the Syrian Armed Forces were estimated at 295,000 regular troops and 314,000 reservists. While the higher positions in the army were mostly occupied by Alawites, the ground troops were mostly made up of Sunnis, and once the uprisings began, the Syrian regime hesitated to employ these troops against the Sunni rebels. Therefore, the army relied on loyal elite units and Alawite militias such as the Shabiha. Due to defections following the uprisings, by the end of 2013 the number of regular troops had decreased to around 110,000. As of 2024, the Syrian Army was estimated at 169,000 active troops. Most of the divisions in the army were under-strength, but Russia had been assisting in the reconstruction and re-equipment of some divisions until the fall of the Assad regime in late 2024, whereupon the Syrian Arab Armed Forces surrendered and were de facto dissolved by the Syrian Opposition groups.

In the aftermath, former government-held regions came under the control of different opposition factions. Some former SAA personnel were absorbed into new defense forces. Efforts to form a centralized transitional military command were ongoing as of early 2025.

National Defense Forces

The Syrian NDF (Arabic: قوات الدفاع الوطني Quwāt ad-Difāʿ al-Watanī) was formed out of pro-government militias in November 2012. The forces acted in an infantry role, directly fighting against rebels on the ground and running counter-insurgency operations in coordination with the army, who provided them with logistical and artillery support. Many of the fighters were trained in Iran, and they received their salaries and military equipment from the Syrian government. As of 2024, the NDF numbered around 50,000 troops. The forces had a 500-strong women's wing called "Lionesses of National Defense" which operated checkpoints. The NDF were mostly made up of Alawites, but many of the Syrian Christian militias (such as Sootoro in Al-Hasakah) also fought on the Syrian government's side to defend their ancient towns, villages and farmsteads from ISIL (see also Christian Militias in Syria).Christian militias lend muscle to Syrian regime in ongoing battle against rebels. The Irish Times. 9 June 2014.

Shabiha

The Shabiha (Levantine Arabic: , ; also romanized Shabeeha or Shabbiha; ) are unofficial pro-government militias drawn largely from Syria's Alawite minority group. Since the uprising, the Baathist Syrian government has been accused of using Shabiha to break up protests and enforce laws in resistive neighborhoods. As the protests escalated into an armed conflict, the opposition started using the term Shabiha to describe civilians they suspected of supporting Bashar al-Assad and the Syrian government and clashing with pro-opposition demonstrators. The opposition blames the Shabiha for the many violent excesses committed against anti-government protesters and opposition sympathizers, as well as for looting and destruction.

The Shabiha phenomenon started in the 1980s, not as one specific group but as a number of criminal and semi-criminal groups affiliated with the Assad clan. Bassel al-Assad attempted to curtail their activities in the 1990s but did not fully succeed. The Shabiha have been described as "a notorious Alawite paramilitary, who are accused of acting as unofficial enforcers for Assad's government"; "gunmen loyal to Assad", and, according to the Qatar-based Arab Center for Research and Policy Studies, "semi-criminal gangs thugs close to the government". Despite the group's image as an Alawite militia, some Shabiha operating in Aleppo have been reported to be Sunnis.

By the late 2010s, many Shabiha groups were integrated into formal pro-government militias such as the National Defence Forces (NDF). Despite this integration, independent Shabiha networks continued to operate in some regions into the early 2020s, often engaging in smuggling, extortion, and looting. Human rights organizations have continued to document allegations of abuses by former Shabiha elements now active within other paramilitary structures.

Hezbollah

Hezbollah is an Iran-backed Shia armed group and political force based in Lebanon. On 25 May 2013, its leader Hassan Nasrallah confirmed that Hezbollah troops were fighting with the Syrian army against Islamic extremists and pledged that "his group will not allow Syrian militants to control areas that border Lebanon". In the televised address, he said, "If Syria falls in the hands of America, Israel and the takfiris, the people of our region will go into a dark period." He also called on Shiites and Hezbollah to protect the shrine of Sayida Zeinab. President Bashar al-Assad had denied earlier that May that there were foreign fighters, Arab or otherwise, fighting for the government in Syria.

Hezbollah's decision to aid the Syrian government is most likely due to the fact that they enjoy the protection of the government when it comes to the group's arms procurement and storage in Syria. Syria forms an important access corridor between Hezbollah in Lebanon and their supporter, Iran, and the survival of a regime that was friendly to Hezbollah was in the group's best interest.

In 2012 and 2013, Hezbollah was active in gaining control of territory in the Homs Governorate in Syria."Hezbollah fighters, Syrian rebels killed in border fighting" . Al Arabiya, 17 February 2013. Retrieved 18 February 2013. By May 2013 the group was publicly collaborating with the Syrian Army and helping them to gain control of 60 percent of Al-Qusayr by 14 May. In Lebanon, an increase in the funerals of Hezbollah fighters was reported, as well as the shelling of Hezbollah-controlled areas by Syrian rebels.

According to independent analysts, by the beginning of 2014, approximately 500 Hezbollah fighters had died in the Syrian conflict. In 2014, Nasrallah claimed the Hezbollah fighters had helped Assad take back control over the country, and that the Syrian regime was no longer in danger of being toppled. The current number of Hezbollah troops in Syria is estimated to be around 7000-8000.

After 2014, Hezbollah's involvement in Syria continued to grow, with the group playing a significant role in major military offensives, such as the Battle of Aleppo (2016) and the Syrian government's recapture of eastern Ghouta (2018). The group also became increasingly involved in securing areas near the Syrian-Lebanese border. By 2020, Hezbollah's forces were reported to be involved in the defense of strategic military positions and continued to provide military assistance to Syrian forces, despite growing opposition from Syrian rebel groups.

The Return Forces () was a Palestinian group founded by Hezbollah in July 2015 and led by Abu Dhikra. It called for the Palestinian return and fought against Syrian opposition. The group fought in Yarmouk and Abu Kamal.

Iran

Since the civil uprising phase of the Syrian civil war, Iran has provided the Syrian Arab Republic with financial, technical, and military support, including the training and sending of combat troops. Iran and Syria are close strategic allies, as Iran sees the survival of the Assad government as being crucial to its regional interests.Iranian Strategy in Syria , Institute for the Study of War, Executive Summary + Full report, May 2013Iran boosts support to Syria, The Daily Telegraph, 21 February 2014 Iran's supreme leader, Ali Khamenei, was reported to be vocally in favor of the Baathist government.

By December 2013, Iran was thought to have approximately 10,000 operatives in Syria. But according to Jubin Goodarzi, assistant professor and researcher at Webster University, Iran aided Baathist Syria with a limited number of deployed units and personnel, "at most in the hundreds ... and not in the thousands as opposition sources claimed". Lebanese Hezbollah fighters backed by Tehran have taken direct combat roles since 2012.Iran boosts military support in Syria to bolster Assad , Reuters, 21, Feb 2014 In the summer of 2013, Iran and Hezbollah provided important battlefield support for Syrian forces, allowing them to make advances on the opposition. In 2014, coinciding with the peace talks at Geneva II, Iran has stepped up support for Syrian President Assad. The Syrian Minister of Finance and Economy stated more than 15 billion dollars had come from the Iranian government.; syrianef; 24, January 2014 Prior to his assassination, Islamic Revolutionary Guard Corps's Quds Force commander Qasem Soleimani was in charge of Syrian President Assad's security portfolio and oversaw the arming and training of thousands of pro-government Shi'ite fighters.

By 2015, 328 IRGC troops, including several commanders, had reportedly been killed in the Syrian civil war since it began. As of 2024, the estimated number of Iranian troops in Syria is 1500.

Foreign Shia militias

Besides training and sending troops, Iran has also recruited Shia fighters from Iraq, Afghanistan and Pakistan to fight on behalf of the Syrian Arab Republic. The number of Afghans fighting in Syria has been estimated at "between 10,000 and 18,000" at its height, but is currently estimated between 500 and 1500. The main force composed of Afghan fighters is the liwa' fatimiyun (Fatemiyoun Brigade), which was found in late 2012. The number of Pakistani fighters is much lower, between 800 and 2500, and concentrated in the liwa' zaynabiyun (Zaynabiyun Brigade) formed in November 2015. Many or most of the fighters were refugees living in Iran, and survivors and defectors of the Fatemiyoun reported being coerced or bribed into joining the militia, and being sent to the most dangerous front lines with little to no training.

After 2015, the number of foreign Shia fighters in Syria continued to fluctuate. Liwa Fatemiyoun, composed mostly of Afghan fighters, remained one of the largest foreign Shia militias in Syria, playing key roles in offensives such as the recapture of Aleppo and the battle for Deir ez-Zor. Liwa Zaynabiyun, primarily consisting of Pakistani fighters, also participated in key battles, with estimates of their numbers ranging between 800 and 2500 fighters as of 2020. Reports indicate that some fighters, particularly from the Fatemiyoun Brigade, continued to be recruited under coercion or financial incentives, facing high casualty rates in combat.

Russia