The Adana massacre (Armenian: Ադանայի կոտորած; Turkish: Adana Katliamı) occurred in the Adana vilayet of the Ottoman Empire in April 1909. Many Armenians were slain by Ottoman Muslims in the city of Adana as the Ottoman countercoup of 1909 triggered a series of pogroms throughout the province. Between 20,000 and 30,000 ethnic Armenians and 1,300 Assyrians were killed and tortured in Adana and the surrounding towns. Unlike the previous Hamidian massacres, the events were not officially organized by the central government, but culturally instigated via local officials, Islamic clerics, and supporters of the Committee of Union and Progress (CUP).

After revolutionary groups had secured the deposition of Sultan Abdul Hamid II and the restoration of the Second Constitutional Era (Ottoman Empire) in 1908, a military revolt directed against the Committee of Union and Progress seized Constantinople. While the revolt lasted only ten days, it reignited anti-Armenian sentiment in the region and precipitated the mass destruction of Armenian businesses and farms, public hangings, sexual violence, and executions rooted in political, economic, and religious prejudice. These massacres continued for more than one month.

In July 1909, the Young Turk government announced the trials of various government and military officials, for being implicated in the massacres; however, the modern Turkish government and certain Turkish nationalists, deny the massacre happened.

After the Hamidian massacres, the Great Powers (Britain, France, Russia) forced Abdul Hamid II to sign a new reform package designed to curtail the powers of the Hamidiye in October 1895 which, like the Berlin treaty, was never implemented. On 1 October 1895, two thousand Armenians assembled in Constantinople (Istanbul) to petition for the implementation of the reforms, but Ottoman police units converged on the rally and violently broke it up. Upon receiving the reform package, the sultan remarked, "This business will end in blood."

In 1908, the Committee of Union and Progress came to power in the Young Turk Revolution. Within a year, the Ottoman Empire's Armenian population, empowered by the dismissal of Abdul Hamid II, began organizing politically in support of the new government, which promised to place them on equal legal footing with their Muslim counterparts.

Having long endured so-called dhimmi status, and having suffered the brutality and oppression of Hamidian leadership since 1876, the Armenians in Cilicia welcomed the liberal reforms proposed by the nascent Young Turk government. With Christians now being granted the right to arm themselves and form politically significant groups, it was not long before Abdul Hamid loyalists, themselves acculturated into the system that had perpetrated the Hamidian massacres of the 1890s, came to view the empowerment of the Christians as coming at their expense.^{[citation needed]}

The countercoup of 1909 wrested control of the government from the secularist Young Turks, and Abdul Hamid II briefly recovered his dictatorial powers. Appealing to the reactionary Muslim population with populist rhetoric calling for the re-institution of Islamic law under the banner of a pan-Islamic caliphate, the Sultan mobilized popular support against the Young Turks by identifying himself with the historically Islamic character of the state.

Many of the Christian Armenians were hopeful of more equality after the coup against Sultan Abdul Hamid II, which removed the Islamic head of state from power. However, the rise of Turkish nationalism and a popular perception of the Armenians as a separatist, European-controlled entity contributed to the malevolence of their attackers.