Neo-Ottomanism (Turkish: Yeni Osmanlıcılık or neo-Osmanlıcılık) is a reactionary, revisionist, monarchist, conservative and Islamist political ideology in Turkey that discredits the Turkish secular nationalist republic and its reforms, and glorifies the Ottoman dynasty and its traditionalist establishments like the caliphate. It is also an irredentist and imperialist ideology that, in its broadest sense, advocates to honor the Ottoman past of Turkey and promotes the greater political engagement of the Republic of Turkey within regions formerly under the rule of the Ottoman Empire, the predecessor state that covered the territory of modern Turkey among others.

Neo-Ottomanism emerged at the end of the Cold War with the dissolution of the Soviet Union, forming two distinct waves of the ideology: the first, in the early 1990s, developed by the Turkish journalist and foreign policy advisor to President Turgut Özal, Cengiz Çandar; the second, associated with Ahmet Davutoğlu, former president of Turkey and founder of the Future Party. Davutoğlu's foreign policy goals include establishing Turkey as an influential power within the Balkans, Caucasia and the Middle East.

The term has been associated with Recep Tayyip Erdoğan's irredentist, interventionist, Pan-Islamist and expansionist foreign policy in the Eastern Mediterranean and the neighboring Cyprus, Greece, Iraq, Syria, as well as in Africa, including Libya, and Nagorno-Karabakh. However, the term has been rejected by members of the Erdoğan government, such as the former Foreign Minister Ahmet Davutoğlu and the former Parliament Speaker Mustafa Şentop.

One of the first uses of the term was in a Chatham House paper by David Barchard in 1985, in which Barchard suggested that a "Neo-Ottoman option" might be a possible avenue for Turkey's future development. It seems also to have been used by the Greeks sometime after Turkey's invasion of Cyprus in 1974.

In the 21st century, the term has come to signify a domestic trend in Turkish politics, where the revival of Ottoman traditions and culture has been accompanied by the rise of the Justice and Development Party (Turkish: Adalet ve Kalkınma Partisi, abbreviated AKP founded in 2001) which came to power in 2002. The use of the ideology by Justice and Development Party has mainly supported a greater influence of Ottoman culture in domestic social policy which has caused issues with the secular and republican credentials of modern Turkey. The AKP have used slogans such as Osmanlı torunu ("descendant of the Ottomans") to refer to their supporters and also their leader Recep Tayyip Erdoğan (who was elected President in 2014) during their election campaigns. These domestic ideals have also seen a revival of neo-Ottomanism in the AKP's foreign policy. Besides acting as a clear distinction between them and ardent supporters of secularism, the social Ottomanism advocated by the AKP has served as a basis for their efforts to transform Turkey's existing parliamentary system into a presidential system, favouring a strong centralised leadership similar to that of the Ottoman era. Critics have thus accused Erdoğan of acting like an "Ottoman sultan".

Neo-Ottomanism has been used to describe Turkish foreign policy under the Justice and Development Party which took power in 2002 under Erdoğan, who subsequently became Prime Minister. Neo-Ottomanism is a dramatic shift from the traditional Turkish foreign policy of the Kemalist ideology, which emphasized looking westward towards Europe. The shift away from this concept in Turkish foreign policy under Turgut Özal's government has been described as the first step towards neo-Ottomanism. Özal's neo-Ottomanism is characterized by a rediscovery of Turkey's multiple identities, in contrast to the unitary conception of the Kemalist republic, and by a tendency to prioritize economic aspects rather than politico-state and security logics.

Neo-Ottomanism had a basis in religious circles. Fethullah Gülen, an influential Islamic leader, looks both to personal transformation and social and political activism, and fully embraces Turkish nationalism—the defining characteristic of which is Islam, not nationality—and economic neoliberalism while stressing continuity with Turkey's Ottoman past. His emphasis on the role of the state and neoliberalism are legacies of the changing nature of the late Ottoman state from the vantage point of the east, including conflicts between Muslims and Christians in Yugoslavia and, later, the expansion of the Soviet Union and the threat it posed.

The Ottoman Empire was an influential global power which, at its peak, controlled the Balkans and most of the modern-day Middle East. Neo-Ottomanist foreign policy encourages increased engagement in these regions as part of Turkey's growing regional influence. This foreign policy contributed to an improvement in Turkey's relations with its neighbors, particularly with Iraq, Iran and Syria. However Turkey's relations with Israel, once Turkey's ally, suffered, especially after the 2008–09 Gaza War and the 2010 Gaza flotilla raid.