Archduke Carl Christian of Austria (German: Carl Christian Maria Anna Rudolph Anton Marcus d'Aviano, Erzherzog und Prinz von Österreich, Prinz von Ungarn, Kroatien, und Böhmen; born 26 August 1954 at Château de Belœil in Belœil, Belgium) is a Belgian aristocrat and a member of the formerly ruling Austro-Hungarian House of Habsburg-Lorraine. He is the third child of Archduke Carl Ludwig of Austria and his wife, Princess Yolande de Ligne.

In 1983, Carl Christian, along with his children, were incorporated by King Baudouin into the Belgian nobility with the title and style of HSH Prince/sse de Habsbourg-Lorraine. To this day, they are considered, together with his cousin Archduke Lorenz and his brother Archduke Rudolf, the founders of the Belgian branch of the Habsburg imperial family.

Carl Christian married his second cousin Princess Marie Astrid of Luxembourg (born 17 February 1954 in Betzdorf), eldest child and daughter of Jean, Grand Duke of Luxembourg and his wife Princess Joséphine-Charlotte of Belgium, on 6 February 1982 in Luxembourg.

They have five children:

Archduchess Marie Christine Anne Astrid Zita Charlotte of Austria (born 31 July 1983 in Brussels), married Count Rodolphe de Limburg-Stirum (born 20 March 1979 in Uccle), son of Count Christian de Limburg-Stirum and Countess Colienne d'Oultremont, on 6 December 2008 in Mechelen They have three sons:
Count Léopold Menno Philippe Gabriel François-Xavier Marie Joseph Ghislain de Limburg-Stirum (born 19 April 2011)
Count Constantin de Limburg-Stirum (born 25 October 2013)
Count Gabriel de Limburg-Stirum (born 2016)
Archduke Imre Emanuel Simeon Jean Carl Marcus d'Aviano of Austria (born 8 December 1985 in Geneva), married Kathleen Elizabeth Walker (born 17 April 1986 in Cincinnati), daughter of Robert Walker, on 8 September 2012 in Washington, DC. They have three daughters:
Archduchess Maria-Stella Elizabeth Christiana Yolande Alberta of Austria (born 11 November 2013 in Kirchberg)
Archduchess Magdalena Maria Alexandra Zita Charlotte of Austria (born 24 February 2016 in Kirchberg)
Archduchess Juliana Marie Christine Wilhelmina Margaret Astrid of Austria (born 14 October 2018 in Geneva)
Archduke Christoph Henri Alexander Maria Marcus d'Aviano of Austria (born 2 February 1988 in Geneva), married Adélaïde Marie Béatrice Drapé-Frisch (born 4 September 1989 in Les Lilas) on 28 December 2012 (civil ceremony) and 29 December 2012 (religious ceremony) in Nancy. They have two daughters:
Archduchess Katarina Marie-Christine Fabiola of Austria (born 22 December 2014)
Archduchess Sophia of Austria (born 30 August 2017)
Archduke Alexander Hector Marie Karl Leopold Marcus d'Aviano of Austria (born 26 September 1990 in Meyrin)
Archduchess Gabriella Maria Pilar Yolande Joséphine Charlotte of Austria (born 26 March 1994 in Geneva), engaged on 22 October 2017 to her second cousin, Prince Henri of Bourbon-Parma (born Roskilde, 14 October 1991). They have a daughter:
Victoria Antonia Marie-Astrid Lydia de Bourbon de Parme (born 30 October 2017)