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.

On 28 May 1894 in Brussels, Karl Anton married his cousin Princess Joséphine Caroline of Belgium (Brussels 18 October 1872-Namur 6 January 1958), daughter of Prince Philippe, Count of Flanders and his wife Princess Marie of Hohenzollern-Sigmaringen. Karl Anton and Joséphine Caroline had four children: