- Islamic Army in Iraq (Al-Jaish Al-Islami fil-Iraq)
- Army of the Men of the Naqshbandi Order (Naqshabandiya Army) Sufi/Sunni Naqshbandi Iraqis led by Saddam's former aide Izzat Ibrahim Ad-Douri. It is the largest insurgency group to be compromised of former Ba'athists and is known to have ties with former regime elements.
- Jaish al-Mujahideen
- Mujahideen Battalions of the Salafi Group of Iraq
- Islamic Salafist Boy Scout Battalions (Kataab Ashbal Al Islam Al Salafi)
- Mohammad's Army (aka Jeish Muhammad)
A guerrilla group opposed to the coalition forces, composed primarily of Sunnis believed to have Ba'athist ties.
- Islamic State of Iraq (till Nov '06, Mujahideen Shura Council)
Umbrella organization and de facto state
- Al Qaeda in Iraq
- Jeish al-Fatiheen (Conquering Army)
- Jund al-Sahaba (Soldiers of the Sahaba)
- Katbiyan Ansar Al-Tawhid wal Sunnah (Brigades of Monotheism and Religious Conservatism)
- Jeish al-Taiifa al-Mansoura (Army of the Victorious Sect)
- Monotheism Supporters Brigades
- Saray al-Jihad Group
- al-Ghuraba Brigades
- al-Ahwal Brigades
- Jama'at al-Tawhid wal-Jihad
A now-defunct militant organization led by Abu Musab al-Zarqawi preceding AQI.
- Jamaat Ansar al-Sunna (formerly Jaish Ansar al-Sunna)
- Ansar al-Islam
- Black Banner Organization (ar-Rayat as-Sawda)
- Asaeb Ahl el-Iraq (Factions of the People of Iraq)
- Wakefulness and Holy War
- Abu Theeb's group
- Jaish Abi Baker's group
- Fedayeen Saddam ("Saddam's Men of Sacrifice")
A paramilitary organization loyal to the former Ba'athist regime of Saddam Hussein.
- The Return (al-Awda)
composed of former Ba'ath Party officials, intelligence agents, former members of the Republican Guard, the Special Republican Gaurd and Fedayeen Saddam militia.
- General Command of the Armed Forces, Resistance and Liberation in Iraq
- Popular Army
- New Return
- Patriotic Front
- Political Media Organ of the Ba‘ath Party (Jihaz al-Iilam al-Siasi lil hizb al-Ba'ath)
- Popular Resistance for the Liberation of Iraq
- Al-Abud Network
- Iraqi Army
The Iraqi Army is a component of the Iraqi Security Forces tasked with assuming responsibility for all Iraqi land-based military operations following the 2003 invasion of Iraq.
- Iraqi Air Force
- Iraqi Police
The Iraqi Police are the organic civil police force of the Republic of Iraq. There are three main branches.
- Iraqi Police Service (IPS): Responsible for the day to day patrolling of cities around most crimes.
- National Police (NP): Paramilitary force for counterinsurgency, public disorder and counter terrorist tasks.
- Supporting Forces: Remaining police organizations, primarily the Department of Border Enforcement (DBE).
- Facilities Protection Service
A paramilitary force responsible for protecting government buildings and facilities.
- Mahdi Army (Jaish-i-Mahdi)(جيش المهدي)
The Mahdi Army is a militia force created by the Iraqi Shia cleric Muqtada al-Sadr in June of 2003, disbanded in 2008.
- Abu Deraa's Mahdi Army faction
In the fall of 2006, Abu Deraa and his supporters formed their own militia.
- Badr Organization (originally Badr Brigade/Bader Corps) (منظمة بدر)
The armed wing of the Islamic Supreme Council of Iraq (SCIRI).
- Sheibani Network
Smuggling network and Insurgent group, which both supplies other insurgents and attacks coalition and Iraqi forces.
- Soldiers of Heaven
an armed Iraqi Shi'a sect.
- Special Groups (Iraq) Iranian backed factions of the Mahdi Army which went on to become separate organisations which continued fighting after the Mahdi Army's disbanding.
- Asa'ib Ahl al-Haq (League of the Righteous)
The largest Special Group, led by Qais Khazali and later Akram al-Kabi.
- Promised Day Brigades
The Special Group which was created as successor of the Mahdi Army and continued activities against US and coalition forces
- Kata'ib Hezbollah (Hezbollah Brigades)
The most notorious Special Group, it became completely independent from the Mahdi Army and other Special Groups.
- Awakening groups
- 1920 Revolution Brigade
- Jaish al-Rashideen
- Islamic Front for the Iraqi Resistance (al-Jabha al-Islamiya lil-Moqawama al-Iraqiya - JAMI)
- Hamas of Iraq
- term used by Kurds to refer to armed Kurdish fighters. The term is now officially used for the security forces of Iraqi Kurdistan.
- Kurdistan Workers' Party or PKK. A militant separatist organization whose goal is the creation of an independent Kurdish state in Turkey. Currently has bases in Iraqi Kurdistan's Qandil mountains.
- Kurdistan Freedom Falcons or TAK. Radical splinter group from PKK, currently residing in Qandil mountains.
- Party for a Free Life in Kurdistan or PJAK. A militant organization whose goal is overthrowing the Islamic government of Iran. Currently taking refuge in the Qandil mountains.
- Qaraqosh Protection Committee, an Assyrian Christian self-defence force
- Malik Al-Tawus Troop, a Yezidi self-defence force in northern Iraq