Frederick William, Prince of Nassau-Weilburg (Friedrich Wilhelm, 25 October 1768, The Hague – 9 January 1816, Weilburg) was a ruler of Nassau-Weilburg. He was created Prince of Nassau and reigned jointly with his cousin, Prince Frederick Augustus of Nassau-Usingen, who became Duke of Nassau. Frederick William died in January 1816, only two months before his cousin. Both men were succeeded by Frederick William's son, William.
On 31 July 1788 in Hachenburg, Frederick William married Burgravine Louise Isabelle of Kirchberg (Hachenburg, 19 April 1772 – Vienna, 6 January 1827). The groom was almost twenty years old and the bride only sixteen. At the time he was still the heir to the principality. His father died on 28 November of the same year and Frederick William succeeded him.
Frederick William and Louise Isabelle had four children:
Friedrich Wilhelm of Nassau-Weilburg, then of Nassau (Bayreuth, 15 December 1799 – Vienna, 6 January 1845). He married on 7 June 1840 Anna Ritter, Edle von Vallyemare (Vienna, 21 June 1802 – Paris, 19 July 1864), created Gräfin von Tiefenbach in 1840, widow of Johann Baptist Brunold. Their only daughter was:
Wilhelmine Brunold (Altzgersdorf, 5 July 1834 – Geneva, 12 December 1892), created in 1844 Gräfin von Tiefenbach, married in Paris on 30 October 1856 and divorced in 1872 Émile de Girardin (né Émile Delamothe) (Paris, 22 June 1802 – Paris, 27 April 1881).
