Syrian rebel

A number of states and armed groups have involved themselves in the ongoing Syrian Civil War as belligerents.

Syrian Arab Republic and allies

A number of sources have emphasized that as of at least late-2015/early-2016 the Syrian Arab Republic was dependent on a mix of volunteers and militias, rather than the Syrian Armed Forces.

Syrian Armed Forces

Before the uprising and war broke out, the Syrian Armed Forces were estimated at 325,000 regular troops and 280,000–300,000 reservists. Of the regular troops, 220,000 were 'army troops' and the rest in the navy, air force and air defense force. Following defections as early as June 2011, the Syrian Observatory for Human Rights estimated that by July 2012, tens of thousands of soldiers had defected.

National Defense Force

The Syrian NDF was formed out of pro-government militias. They receive their salaries and military equipment from the government, and in 2013 numbered around 100,000 troops. The force acts in an infantry role, directly fighting against rebels on the ground and running counter-insurgency operations in coordination with the army, who provides them with logistical and artillery support. The force has a 500-strong women's wing called "''Lionesses of National Defense''" which operates checkpoints. NDF members, like regular army soldiers, are allowed to loot the battlefields (but only if they participate in raids with the army), and can sell the loot for extra money. Sensing that they depend on the largely secular government, many of the militias of Syrian Christians (like Sootoro in Al-Hasakah) fight on the Baathist Syrian government's side and seek to defend their ancient towns, villages and farmsteads from ISIL (see also Christian Militias in Syria).

Shabiha

The ''Shabiha'' 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 restive 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 looting and destruction. In December 2012, the ''shabiha'' were designated a terrorist organization by the United States.

Bassel al-Assad is reported to have created the ''shabiha'' in the 1980s for government use in times of crisis. ''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. In 2012, the Assad government created a more organized official militia known as the Jaysh al-Sha'bi, allegedly with help from Iran and Hezbollah. As with the ''shabiha'', the vast majority of Jaysh al-Sha'bi members are Alawite and Shi'ite volunteers."Iran and Hezbollah build militia networks in Syria, officials say"
''The Guardian''. 12 February 2013. Retrieved 27 February 2013.

Hezbollah

In February 2013, former secretary general of Hezbollah, Sheikh Subhi al-Tufayli, confirmed that Hezbollah was fighting for the Syrian Army, which in October 2012, General Secretary Hassan Nasrallah had still denied was happening on a large scale, except to admit that Hezbollah fighters helped the Assad government "retain control of some 23 strategically located villages n Syriainhabited by Shiites of Lebanese citizenship". Nasrallah said that Hezbollah fighters have died in Syria doing their "jihadist duties".

In 2012 and 2013, Hezbollah was active in gaining control of territory in the Al-Qusayr District of Syria,"Hezbollah fighters, Syrian rebels killed in border fighting"
. Al Arabiya, 17 February 2013. Retrieved 18 February 2013. by May 2013 publicly collaborating with the Syrian Army and taking 60 percent of Qusayr by the end of 14 May. In Lebanon, there have been "a recent increase in the funerals of Hezbollah fighters" and "Syrian rebels have shelled Hezbollah-controlled areas." As of 14 May 2013, Hezbollah fighters were reported to be fighting alongside the Syrian Army, particularly in the Homs Governorate. Hassan Nasrallah has called on Shiites and Hezbollah to protect the shrine of Sayida Zeinab. President Bashar al-Assad denied in May 2013 that there were foreign fighters, Arab or otherwise, fighting for the government in Syria.

On 25 May 2013, Nasrallah announced that Hezbollah was fighting in Syria 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." According to independent analysts, by the beginning of 2014, approximately 500 Hezbollah fighters had died in the Syrian conflict. On 7 February 2016, 50 Hezbollah fighters were killed in a clash by the Jaysh al-Islam near Damascus. These fighters were embedded in the Syrian Army (SAA) formation called Army Division 39.

Iran

Iran continues to officially deny the presence of its combat troops in Syria, maintaining that it provides military advice to Assad's forces in their fight against terrorist groups. Since the civil uprising phase of the Syrian civil war, Iran has provided the Syrian Arab Republic with financial, technical, and military support, including training and some combat troops. Iran and Syria are close strategic allies. 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. 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.

On 6 March 2020, Farhad Dabirian, a commander in IRGC, was killed in Syria. He was previously stationed at Palmyra in Syria.

Foreign Shia militias

Shia fight