According to Acts of Apostles 11, a city in the southern of Turkey, Antioch (now Antakya) is the birthplace of the first Christian community.

In 324, Constantine I chose Byzantium to be the new capital of the Roman Empire, renaming it New Rome. Following the death of Theodosius I in 395 and the permanent division of the Roman Empire between his two sons, the city, which would popularly come to be known as Constantinople, became the capital of the Eastern Roman Empire. This empire, which would later be branded by historians as the Byzantine Empire, ruled most of the territory of present-day Turkey until the Late Middle Ages; although the eastern regions remained in firm Sasanian hands up to the first half of the seventh century. The frequent Byzantine-Sassanid Wars, as part of the centuries long-lasting Roman-Persian Wars, fought between the neighbouring rivalling Byzantines and Sasanians, took place in various parts of present-day Turkey and decided much of the latter's history from the fourth century up to the first half of the seventh century.

The House of Seljuk was a branch of the Kınık Oğuz Turks who resided on the periphery of the Muslim world, in the Yabgu Khaganate of the Oğuz confederacy, to the north of the Caspian and Aral Seas, in the 9th century. In the 10th century, the Seljuks started migrating from their ancestral homeland into Persia, which became the administrative core of the Great Seljuk Empire, after its foundation by Tughril.

In the latter half of the 11th century, the Seljuk Turks began penetrating into medieval Armenia and the eastern regions of Anatolia. In 1071, the Seljuks defeated the Byzantines at the Battle of Manzikert, starting the Turkification process in the area; the Turkish language and Islam were introduced to Armenia and Anatolia, gradually spreading throughout the region. The slow transition from a predominantly Christian and Greek-speaking Anatolia to a predominantly Muslim and Turkish-speaking one was underway. The Mevlevi Order of dervishes, which was established in Konya during the 13th century by Sufi poet Celaleddin Rumi, played a significant role in the Islamization of the diverse people of Anatolia who had previously been Hellenized. Thus, alongside the Turkification of the territory, the culturally Persianized Seljuks set the basis for a Turko-Persian principal culture in Anatolia, which their eventual successors, the Ottomans, would take over.

In 1243, the Seljuk armies were defeated by the Mongols at the Battle of Köse Dağ, causing the Seljuk Empire's power to slowly disintegrate. In its wake, one of the Turkish principalities governed by Osman I would evolve over the next 200 years into the Ottoman Empire. In 1453, the Ottomans completed their conquest of the Byzantine Empire by capturing its capital, Constantinople.

In 1514, Sultan Selim I (1512–1520) successfully expanded the empire's southern and eastern borders by defeating Shah Ismail I of the Safavid dynasty in the Battle of Chaldiran. In 1517, Selim I expanded Ottoman rule into Algeria and Egypt, and created a naval presence in the Red Sea. Subsequently, a contest started between the Ottoman and Portuguese empires to become the dominant sea power in the Indian Ocean, with a number of naval battles in the Red Sea, the Arabian Sea and the Persian Gulf. The Portuguese presence in the Indian Ocean was perceived as a threat to the Ottoman monopoly over the ancient trade routes between East Asia and Western Europe. Despite the increasingly prominent European presence, the Ottoman Empire's trade with the east continued to flourish until the second half of the 18th century.

The Ottoman Empire's power and prestige peaked in the 16th and 17th centuries, particularly during the reign of Suleiman the Magnificent, who personally instituted major legislative changes relating to society, education, taxation and criminal law. The empire was often at odds with the Holy Roman Empire in its steady advance towards Central Europe through the Balkans and the southern part of the Polish-Lithuanian Commonwealth. At sea, the Ottoman Navy contended with several Holy Leagues, such as those in 1538, 1571, 1684 and 1717 (composed primarily of Habsburg Spain, the Republic of Genoa, the Republic of Venice, the Knights of St. John, the Papal States, the Grand Duchy of Tuscany and the Duchy of Savoy), for the control of the Mediterranean Sea. In the east, the Ottomans were often at war with Safavid Persia over conflicts stemming from territorial disputes or religious differences between the 16th and 18th centuries. The Ottoman wars with Persia continued as the Zand, Afsharid, and Qajar dynasties succeeded the Safavids in Iran, until the first half of the 19th century. From the 16th to the early 20th centuries, the Ottoman Empire also fought many wars with the Russian Tsardom and Empire. These were initially about Ottoman territorial expansion and consolidation in southeastern and eastern Europe; but starting from the latter half of the 18th century, they became more about the survival of the Ottoman Empire, which had begun to lose its strategic territories on the northern Black Sea coast to the advancing Russians.

From the second half of the 18th century onwards, the Ottoman Empire began to decline. The Tanzimat reforms of the 19th century, which had been instituted by Mahmud II, were aimed to modernise the Ottoman state in line with the progress that had been made in Western Europe. The efforts of Midhat Pasha during the late Tanzimat era led the Ottoman constitutional movement of 1876, which introduced the First Constitutional Era, but these efforts proved to be inadequate in most fields, and failed to stop the dissolution of the empire. As the empire gradually shrank in size, military power and wealth, especially after the Ottoman economic crisis and default in 1875 which led to uprisings in the Balkan provinces that culminated into the Russo-Turkish War of 1877–78, many Balkan Muslims migrated to the Empire's heartland in Anatolia, along with the Circassians fleeing the Russian conquest of the Caucasus. The decline of the Ottoman Empire led to a rise in nationalist sentiment among its various subject peoples, leading to increased ethnic tensions which occasionally burst into violence, such as the Hamidian massacres of Armenians.

The Young Turk Revolution in 1908 restored the Ottoman constitution and parliament 30 years after their suspension by Sultan Abdul Hamid II in 1878, which is known as the Second Constitutional Era, but the 1913 Ottoman coup d'état effectively put the country under the control of the Three Pashas, making sultans Mehmed V and Mehmed VI largely symbolic figureheads with no real political power.

The Ottoman Empire entered World War I on the side of the Central Powers and was ultimately defeated. During the war, the empire's Armenians were deported to Syria as part of the Armenian Genocide. As a result, an estimated 800,000 to 1,500,000 Armenians were killed. The Turkish government has refused to acknowledge the events as genocide and claims that Armenians were only relocated from the eastern war zone. Genocidal campaigns were also committed against the empire's other minority groups such as the Assyrians and Greeks. Following the Armistice of Mudros on 30 October 1918, the victorious Allied Powers sought to partition the Ottoman state through the 1920 Treaty of Sèvres.

The occupation of Istanbul and Izmir by the Allies in the aftermath of World War I prompted the establishment of the Turkish National Movement. Under the leadership of Mustafa Kemal Pasha, a military commander who had distinguished himself during the Battle of Gallipoli, the Turkish War of Independence was waged with the aim of revoking the terms of the Treaty of Sèvres.

By 18 September 1922 the Greek, Armenian and French armies were expelled, and the Ankara-based Turkish regime, which had declared itself the legitimate government of the country on 23 April 1920, started to formalise the legal transition from the old Ottoman into the new Republican political system. On 1 November 1922, the Turkish Parliament in Ankara formally abolished the Sultanate, thus ending 623 years of monarchical Ottoman rule. The Treaty of Lausanne of 24 July 1923 led to the international recognition of the sovereignty of the newly formed "Republic of Turkey" as the successor state of the Ottoman Empire, and the republic was officially proclaimed on 29 October 1923 in Ankara, the country's new capital. The Lausanne Convention stipulated a population exchange between Greece and Turkey, whereby 1.1 million Greeks left Turkey for Greece in exchange for 380,000 Muslims transferred from Greece to Turkey.

Mustafa Kemal became the republic's first President and subsequently introduced many radical reforms with the aim of transforming the old religion-based and multi-communal Ottoman state system (constitutional monarchy) into an essentially Turkish nation state (parliamentary republic) with a secular constitution. With the Surname Law of 1934, the Turkish Parliament bestowed upon Mustafa Kemal the honorific surname "Atatürk" (Father of the Turks).

İsmet İnönü became Turkey's second President following Atatürk's death on 10 November 1938. In 1939 Turkey annexed the Republic of Hatay. Turkey remained neutral during most of World War II, but entered the closing stages of the war on the side of the Allies on 23 February 1945. On 26 June 1945, Turkey became a charter member of the United Nations. In the same year, the single-party period in Turkey came to an end, with the first multiparty elections in 1946. The Truman Doctrine in 1947 enunciated American intentions to guarantee the security of Turkey and Greece during the Cold War, and resulted in large-scale U.S. military and economic support. In 1948 both countries were included in the Marshall Plan and the OEEC for rebuilding European economies. In 1949 Turkey became a member of the Council of Europe. The Democratic Party established by Celâl Bayar won the 1950, 1954 and 1957 general elections and stayed in power for a decade, with Adnan Menderes as the Prime Minister and Bayar as the President. After participating with the United Nations forces in the Korean War, Turkey joined NATO in 1952, becoming a bulwark against Soviet expansion into the Mediterranean. Turkey subsequently became a founding member of the OECD in 1961, and an associate member of the EEC in 1963.

The country's tumultuous transition to multiparty democracy was interrupted by military coups d'état in 1960, 1971, and 1980, as well as a military memorandum in 1997. Between 1960 and the end of the 20th century, the prominent leaders in Turkish politics who achieved multiple election victories were Süleyman Demirel, Bülent Ecevit and Turgut Özal.

Following a decade of Cypriot intercommunal violence and the coup in Cyprus on 15 July 1974 staged by the EOKA B paramilitary organisation, which overthrew President Makarios and installed the pro-Enosis (union with Greece) Nikos Sampson as dictator, Turkey invaded Cyprus on 20 July 1974 by unilaterally exercising Article IV in the Treaty of Guarantee (1960), but without restoring the status quo ante at the end of the military operation. In 1983 the Turkish Republic of Northern Cyprus, which is recognised only by Turkey, was established. As of 2017, negotiations for solving the Cyprus dispute are still ongoing between Turkish Cypriot and Greek Cypriot political leaders.

In 1984, the Kurdistan Workers' Party (PKK), a Kurdish separatist group (listed as a terrorist organization by NATO, the United States and the European Union), began an armed insurgency campaign against Turkey. The conflict has claimed over 40,000 lives to date.

Since the liberalisation of the Turkish economy in the 1980s, the country has enjoyed stronger economic growth and greater political stability. Turkey applied for full membership of the EEC in 1987, joined the EU Customs Union in 1995 and started accession negotiations with the European Union in 2005.

In 2013, widespread protests erupted in many Turkish provinces, sparked by a plan to demolish Gezi Park but soon growing into general anti-government dissent. On 15 July 2016, an unsuccessful coup attempt tried to oust the government. As a reaction to the failed coup d'état, the government is currently carrying out mass purges.