Prince Ludwig August Maria Eudes of Saxe-Coburg and Gotha (8 August 1845 – 14 September 1907), known in Brazil as Dom Luís Augusto, was a German prince of the House of Saxe-Coburg and Gotha-Koháry and an imperial Brazilian Admiral.

He was born Prince Ludwig August Maria Eudes of Saxe-Coburg and Gotha at the Château d'Eu in France. He was the second son of Prince August of Saxe-Coburg and Gotha and Clémentine of Orléans. His father was a first cousin of Victoria of the United Kingdom and her consort, Prince Albert of Saxe-Coburg and Gotha. Through his mother he was a grandson of Louis-Philippe I, King of the French, the last king to rule France.

Ludwig August and his double first cousin, the French Prince Gaston, comte d'Eu (son of Victoire, sister of August's father) were imported to Brazil in order to marry the two daughters of the Emperor Pedro II of Brazil: Isabel, the elder, and Leopoldina, the younger. The original plan was for August to marry Isabel and Gaston Leopoldina, but the girls decided otherwise and the Emperor, having himself experienced the unhappinesses of an arranged dynastic marriage, agreed to their wishes.

Ludwig August and Leopoldina married in Rio de Janeiro on 15 December 1864, two months after the wedding of Isabel and Gaston. They had four sons:

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