Prince Karl Anton of Hohenzollern-Sigmaringen (German: Karl Anton Friedrich Wilhelm Ludwig Prinz von Hohenzollern-Sigmaringen) (1 September 1868 – 21 February 1919) was a member of the Princely House of Hohenzollern-Sigmaringen. Karl Anton was the third and youngest son of Leopold, Prince of Hohenzollern and his wife Infanta Antónia of Portugal. Karl Anton's elder brothers were William, Prince of Hohenzollern and Ferdinand I of Romania.