The Republican People's Party (Turkish: Cumhuriyet Halk Partisi, pronounced [dumhuijet hak 'patisi] (listen), acronymized as CHP [dehepe]) is a Kemalist and social-democratic political party in Turkey which currently stands as the main opposition party. It is also the oldest political party in Turkey, founded by Mustafa Kemal Atatrk, the first president and founder of the modern Turkish Republic. The party is also cited as the founding party of modern Turkey. The CHP describes itself as a ''modern social-democratic party, which is faithful to the founding principles and values of the Republic of Turkey". Its logo consists of the Six Arrows, which represent the foundational principles of Kemalism: republicanism, reformism, laicism (Lacit/Secularism), populism, nationalism, and statism. It is the main opposition party to the ruling conservative Justice and Development Party (AKP) in the Grand National Assembly with 135 MPs.

The political party has its origins in the various resistance groups founded during the Turkish War of Independence. Under the leadership of Mustafa Kemal Atatrk they united in the 1919 Sivas Congress. On 9 September 1923, the "People's Party declared itself to be a political organisation and on 29 October 1923, announced the establishment of the Turkish Republic, with Atatrk as its first president. In 1924, the People's Party renamed itself the "Republican People's Party". As Turkey moved into its one-party period, the CHP was the apparatus of implementing far reaching political, cultural, social, and economic reforms in the country.

After World War II, Atatrk's successor, smet nn, allowed for multi-party elections, and the party initiated a peaceful transition of power after losing the 1950 election, ending the one-party period and starting Turkey's multi-party period. The years following the 1960 military coup saw the party gradually trend towards the center-left, which was cemented once Blent Ecevit became chairman in 1972. The CHP, along with all other political parties of the time, was banned by the military junta of 1980. The CHP was re-established with its original name and a more centrist outlook by Deniz Baykal on 9 September 1992, with the participation of a majority of its members from the pre-1980 period. Kemal Kldarolu has returned the party back to its traditional centre-left position when he took over in 2011.

It is a founding party of the Nation Alliance, a coalition consisting of opposition parties like the Good Party, Felicity Party, and Democrat Party against the ruling AKP and their Peoples Alliance. In addition, CHP is an associate member of the Party of European Socialists (PES), a member of the Socialist International, and the Progressive Alliance. Many politicians of CHP have declared their support for LGBT rights and the feminist movement in Turkey. The party continues its Pro-European policies and commitment to NATO.

The party's base includes the middle and upper-middle classes such as white-collar workers, retired generals, government bureaucrats, academics, college students, left-leaning intellectuals, labour unions such as DSK, and Alevis. The party's strongholds include the Western Aegean region (zmir, Aydn, Mula), Thrace, the east of the Black Sea Region (Ardahan and Artvin), and the Anatolian college town of Eskiehir.

Kemal Atatürk (or alternatively written as Kamâl Atatürk, Mustafa Kemal Pasha until 1934, commonly referred to as Mustafa Kemal Atatürk; c. 1881 – 10 November 1938) was a Turkish field marshal, revolutionary statesman, author, and the founding father of the Republic of Turkey, serving as its first president from 1923 until his death in 1938. He undertook sweeping progressive reforms, which modernized Turkey into a secular, industrializing nation. Ideologically a secularist and nationalist, his policies and socio-political theories became known as Kemalism. Due to his military and political accomplishments, Atatürk is regarded as one of the most important political leaders of the 20th century.Atatürk came to prominence for his role in securing the Ottoman Turkish victory at the Battle of Gallipoli (1915) during World War I. Following the defeat and dissolution of the Ottoman Empire, he led the Turkish National Movement, which resisted mainland Turkey's partition among the victorious Allied powers. Establishing a provisional government in the present-day Turkish capital Ankara (known in English at the time as Angora), he defeated the forces sent by the Allies, thus emerging victorious from what was later referred to as the Turkish War of Independence. He subsequently proceeded to abolish the decrepit Ottoman Empire and proclaimed the foundation of the Turkish Republic in its place.

As the president of the newly formed Turkish Republic, Atatürk initiated a rigorous program of political, economic, and cultural reforms with the ultimate aim of building a modern, progressive and secular nation-state. He made primary education free and compulsory, opening thousands of new schools all over the country. He also introduced the Latin-based Turkish alphabet, replacing the old Ottoman Turkish alphabet. Turkish women received equal civil and political rights during Atatürk's presidency. In particular, women were given voting rights in local elections by Act no. 1580 on 3 April 1930 and a few years later, in 1934, full universal suffrage.His government carried out a policy of Turkification, trying to create a homogeneous, unified and above all secular nation. Under Atatürk, the few surviving indigenous minorities were pressured to speak Turkish in public; non-Turkish toponyms and last names of minorities had to be changed to Turkish renditions. The Turkish Parliament granted him the surname Atatürk in 1934, which means "Father of the Turks", in recognition of the role he played in building the modern Turkish Republic. He died on 10 November 1938 at Dolmabahçe Palace in Istanbul, at the age of 57; he was succeeded as president by his long-time Prime Minister İsmet İnönü and was honored with a state funeral.

In 1981, the centennial of Atatürk's birth, his memory was honoured by the United Nations and UNESCO, which declared it The Atatürk Year in the World and adopted the Resolution on the Atatürk Centennial, describing him as "the leader of the first struggle given against colonialism and imperialism" and a "remarkable promoter of the sense of understanding between peoples and durable peace between the nations of the world and that he worked all his life for the development of harmony and cooperation between peoples without distinction". He was also praised for condemning the atrocities against Armenians.