Guillaume Hereditary Grand Duke of Luxembourg
- Category : 1981-births
- Type : PSP
- Profile : 1/3 - Investigating / Martyr
- Definition : Split - Small (20)
- Incarnation Cross : RAX Explanation 4
Luxembourgian prince who has been heir apparent to the crown of Luxembourg since his father's accession in 2000. Prince Guillaume is the eldest child of Grand Duke Henri of Luxembourg and his wife, Cuban-born Grand Duchess Maria Teresa. He was named after his father's youngest brother Prince Guillaume of Luxembourg. Guillaume has four younger siblings: Prince Félix, Prince Louis, Princess Alexandra and Prince Sébastien.
On 26 April 2012, the court announced the engagement of the Hereditary Grand Duke to the Belgian Countess Stéphanie de Lannoy. They share a common descent from Charles Marie, Prince & 5th Duke d’Arenberg, which means that Stéphanie and Guillame's father are 7th cousins. The civil wedding took place on 19 October 2012; the religious wedding took place on 20 October 2012.
Their first child, a son, named Prince Charles Jean Philippe Joseph Marie Guillaume, was born at 5:13 AM on 10 May 2020 in Luxembourg City, as the second in the line of succession to the throne, behind his father.