The Republican People's Party is a Kemalist and social democratic political party in Turkey. It is the oldest political party in Turkey, founded by Mustafa Kemal Atatürk, the first president and founder of the modern Turkish Republic. The party is also cited as the founding party of modern Turkey. Its logo consists of the Six Arrows, which represent the foundational principles of Kemalism: republicanism, reformism, laicism (Laïcité/Secularism), populism, nationalism, and statism. It is currently the second largest party in Grand National Assembly with 126 MPs, behind the ruling conservative Justice and Development Party.

The one-party period of the Republic of Turkey began with the formal establishment of the country in 1923. The Republican People's Party (CHP) was the only party between 1923 and 1945, when the National Development Party was established. After winning the first multiparty elections in 1946 by a landslide, the Republican People's Party lost the majority to the Democratic Party in the 1950 elections. During the one-party period, President Mustafa Kemal Atatürk repeatedly requested that opposition parties be established to stand against the Republican People's Party in order to transition into multi-party democracy. Kâzım Karabekir established the Progressive Republican Party in 1924 but it was banned after its members' involvement in the 1925 Sheikh Said rebellion. In 1930 the Liberal Republican Party was established but then dissolved again by its founder. Despite Atatürk's efforts to establish a self-propagating multi-party system, this was only established after his death in 1938.