Turkish nationalism (Turkish: Türk milliyetçiliği) is nationalism among the people of Turkey and individuals whose national identity is Turkish. Turkish nationalism consists of political and social movements and sentiments prompted by a love for Turkish culture, Turkish language and history, and a sense of pride in Turkey and Turkish people. While national consciousness in Turkish nation can be traced back centuries, nationalism has been a predominant determinant of Turkish attitudes mainly since the 20th century. Modern Turkish nationalism rose during the Tanzimat era. It also has a complicated relationship with Muslim identity, Pan-Turkism, and Turanism.

After the fall of the Ottoman Empire, Mustafa Kemal Atatürk came to power. He introduced a language reform with the aim to "cleanse" the Turkish language of foreign (mostly Arabic and Persian) influence. He also promoted the Turkish History Thesis in Turkish political and educational circles from 1930s. Turkish researchers at the time like Hüseyin Cahit Yalçın and Rıfat Osman Bey also came up with the idea that Early Sumerians were proto-Turks.

The early Turkish nationalists were typically secular and often influenced by Ziya Gökalp (1876–1924). Gökalp aimed for the Turkification of Islam; that the Quran should be translated from Arabic into Turkish, and that the adhan should be recited in Turkish instead of Arabic from the Minarets. During the early years of the republic, religious traditions were not important and Turkish nationalists were much more open to the westernization of the Turkish society.

Ideologies associated with Turkish nationalism include Pan-Turkism or Turanism (a form of ethnic or racial essentialism or national mysticism), Turkish–Islamic nationalism (which combines Turkish nationalism with Islamic identity), Anatolianism (which considers the Turkish nation as a separate entity which developed after the Seljuk conquest of Anatolia in the 11th century), and secular, civic nationalist Kemalism (which defines the "Turks" as the national identity of the people of Turkey). The term "ultranationalism" is often used to describe Turkish nationalism.

Implemented by Atatürk, the founding ideology of the Republic of Turkey features nationalism (Turkish: milliyetçilik) as one of its six principles. Following the proclamation of the republic in 1923, the Kemalism or "Turkish state nationalism" became the official state ideology and the guiding principle behind the widespread socio-political reforms.

The Kemalist revolution aimed to create a nation state from the remnants of the multi-religious and multi-ethnic Ottoman Empire. Kemalist nationalism originates from the social contract theories, especially from the civic nationalist principles advocated by Jean-Jacques Rousseau and his Social Contract. The Kemalist perception of social contract was effected by the dissolution of the Ottoman Empire which was perceived as a product of failure of the Ottoman "Millet" system and the ineffective Ottomanism policy. Kemalist nationalism, after experiencing the Ottoman Empire's breakdown, defined the social contract as its "highest ideal".^{[citation needed]}

In the 1930s Kemalism became an all-encompassing state ideology based on Atatürk's sayings and writings. The Kemalist definition of nationality was integrated to Article 66 of the Constitution of the Republic of Turkey. Legally, every citizen is defined as a Turk, regardless of ethnicity or religion. Turkish nationality law states that he or she can be deprived of his/her nationality only through an act of treason.

Kemalist nationalism believes in the principle that the Turkish state is an indivisible whole comprising its territory and people, which is defined as the "unity of the state".