Collaboration with the Islamic State refers to the cooperation and assistance given by governments, non-state actors, and private individuals to the Islamic State (IS) during the Syrian Civil War, War in Iraq, and Libyan Civil War.

During the Syrian civil war, the Syrian opposition and some analysts had accused President Bashar al-Assad and the Ba'athist regime of strategically releasing Islamist prisoners during the start of the Syrian crisis in an attempt to strengthen jihadist factions over other rebels. The Syrian opposition have also accused Assad of having intelligence operatives within the ranks of IS, and even directing IS attacks. However, "despite repeated announcements by opposition figures", there exists "no solid evidence ... that the jihadists as a whole are controlled by the [Syrian] regime.

The Assad government has also been accused of funding IS through oil purchases. Western officials stated in 2015 that the Syrian government and IS jointly ran a gas plant in Tabqah using intermediates to supply electricity to both Ba'athist and IS-held areas. A report in 2015 suggested that IS kept gas flowing to Assad regime-controlled power stations. Furthermore, IS allowed grain to pass from Rojava to government-controlled areas at the cost of a 25% levy. IS defectors interviewed by academics in 2015 and 2016 reported being "disillusioned by... upsetting alliances that included the sale of wheat stores and oil to Assad, oil some of which later found its way into barrel bombs raining down on Syrian civilians." This was confirmed in 2016 in Wall Street Journal reporting of documents extracted by US Special Forces in raids on IS operatives. In 2017, US and European officials said that oil sales to the Syrian government were IS's largest source of revenue.

An unpublished IHS Jane's Terrorism and Insurgency Center database analysis showed that only 6% of Syrian government forces attacks were targeted at IS from January to November 2014, while in the same period only 13% of all IS attacks targeted government forces. Academics who interviewed IS defectors in 2015–16 said their interviewees "observed regime forces strangely giving up territory to ISIS without much of a fight, and even leaving their weapons for ISIS rather than destroying them." Aymenn Jawad Al-Tamimi had disputed such assertions in 2014, arguing that "ISIS has a record of fighting the regime on multiple fronts", many rebel factions have engaged in oil sales to the Syrian regime because it is "now largely dependent on Iraqi oil imports via Lebanese and Egyptian third-party intermediaries", and while "the regime is focusing its airstrikes [on areas] where it has some real expectations of advancing" claims that it "has not hit ISIS strongholds" are "untrue". He concluded: "Attempting to prove an ISIS-regime conspiracy without any conclusive evidence is unhelpful, because it draws attention away from the real reasons why ISIS grew and gained such prominence: namely, rebel groups tolerated ISIS." Similarly, Max Abrahms and John Glaser stated in the Los Angeles Times in December 2017 that "The evidence of Assad sponsoring Islamic State... was about as strong as for Saddam Hussein sponsoring Al Qaeda". According to an April 2017 IHS Markit report, IS fought Syrian government forces more than any other opponent between April 1, 2016, and March 31, 2017: "43 percent of all Islamic State fighting in Syria was directed against President Assad's forces, 17 against the U.S.-backed Syrian Democratic Forces (SDF) and the remaining 40 percent involved fighting rival Sunni opposition groups".

Israeli public officials often accused the Palestinian government in Gaza (led by Hamas) of collaborating with, or resembling IS. "Hamas is ISIS" was first asserted by Benjamin Netanyahu near the end of the 2014 Gaza War. The comparison was criticized and mocked by some Israeli journalists. Netanyahu followed this by saying, “Hamas is ISIS and ISIS is Hamas”, in a 2014 speech at the United Nations. In reference to this, the head of the Department of Political Science at Hebron University, said it was "dangerous" to conflate Hamas and IS. Israeli journalists pointed out that Hamas more closely resemble the Irgun and Lehi more closely than Hamas resemble IS.

Occasionally Egyptian public officials have accused Hamas of assisting IS in the Sinai, but in public the two groups had a violently hostile relationship. Israeli Major General Yoav “Polly” Mordechai also accused people in Gaza of helping IS by providing medical care to people wounded in the Sinai conflict. However, medical ethics and international law supports providing treatment for all wounded, including irregular combatants.

In the first days following the October 7 attacks and start of the Gaza War, The Jerusalem Post quoted Benjamin Netanyahu saying, “They are savages. Hamas is ISIS”, the article then highlighted some alleged similarities in the groups' influences identified by Dr. Harel Chorev (from the Moshe Dayan Center for Middle Eastern Studies at Tel Aviv University). Netanyahu included this assertion in a public addresses in the United States made alongside Secretary Antony J. Blinken, in the first week of the Israeli bombing of the Gaza Strip. Netanyahu said, "Hamas is ISIS, and just as ISIS was crushed, so too will Hamas be crushed".

International military experts and mainstream international media pointed out major differences, particularly relating to nationalism, Shia Islam, Christianity, democracy, and destruction of cultural heritage. IS want a purely theocratic system of government without any element of democracy, and IS violently attack Christians, whereas Hamas participated in the 2006 Palestinian legislative election and the Hamas-led electoral list that won the election included a Palestinian Christian running for the Christian reserved seat in Gaza City. Talal Abu Zarifa, a leader from the DFLP (a secular faction allied to Hamas), said Israel was using the comparison to "justify its annihilation of Palestinian people and bloodshed".