Racu (Hungarian: Csíkrákos, Hungarian pronunciation: [ˈtʃiːkraːkoʃ], meaning "Place with the Crabs of Csík") is a commune in Harghita County, Transylvania, Romania.

The villages were part of the Székely Land region of the historical Transylvania province.

After the administrative reform of Transylvania in 1876, they fell within the Csík County in the Kingdom of Hungary.

After the Treaty of Trianon of 1920, they became part of Romania and fell within Ciuc County during the interwar period.

After Soviet occupation, the Romanian administration returned and the commune became officially part of Romania in 1947.