Prince Ludwig Gaston of Saxe-Coburg and Gotha (Ludwig Gaston Klemens Maria Michael Gabriel Raphael Gonzaga; 15 September 1870 – 23 January 1942), known in Brazil as Dom Luís Gastão, was a German prince of the House of Saxe-Coburg and Gotha-Koháry, and the last surviving grandchild of Emperor Pedro II of Brazil.

Shortly after their mother's death in 1871, Ludwig and his brothers moved to Brazil, where they lived with their maternal grandfather until a military coup d'état in 1889 abolished the monarchy, forcing the imperial family into exile.

In Munich, on 1 May 1900, the prince married Princess Mathilde, daughter of King Ludwig III of Bavaria.

[4] They had two children, a son and a daughter: After the death of his first wife in 1906, he married for a second time to Countess Anna of Trauttmansdorff-Weinsberg (1873–1948), daughter of Karl Johann Nepomuk Ferdinand, Prince von und zu Trauttmansdorff-Weinsberg and his wife Josephine, Markgräfin von Pallavicini, (1849–1923) at Bischofteinitz on 30 November 1907.

By birth, Anna was member of an ancient House of Trauttmansdorff-Weinsberg, one of the most prominent Austrian princely families.