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d'Udekem
noble family
Coat of Arms of the comital branch since 1999[1]
Country	Belgium
Current head	Bernard, Count d'Udekem d'Acoz
Titles	Count, mostly jonkheer
Estate(s)	Losange Castle, Couthof Castle, Raepenburg Castle.[2]
Cadet branches	d'Udekem d'Acoz d'Udekem Gentinnes d'Udekem de Guertechin

The House d'Udekem (French: [dyd(ə)kɛm]) is the name of a noble family that has belonged to the nobility of Belgium since 1816.

The origin of the d'Udekem family dates back to the Late Middle Ages, with the earliest member recorded Gooris van Udekem (†1472), who, in 1468, purchased the Lordship of Guertechin in Bossut. In the 18th century the Dominium of Acoz was obtained via marriage by the family. The first elevation of a member of the family to the French nobility took place in 1716, but this branch became extinct in the male line in 1803. The French Revolution meant the abolition of the family's noble status in 1795, but it was later restored under the rule of King William I of the Netherlands.

Until 2000, the head of the d'Udekem family held the rank of Baron. After the wedding of Mathilde d'Udekem d'Acoz with the Duke of Brabant, King Albert II extended the hereditary title of Count to the three brothers Henri, Raoul and Patrick d'Udekem d'Acoz and to all their descendants.^[3]

Members of the family were active in politics.

• 
  Losange Castle, private property of the dowager Countess Anna Maria d’Udekem d’Acoz
• 
  Acoz Castle, home of d'Udekem d'Acoz family from 1760 until 1860
• 
  Couthof Castle, residence of d'Udekem family since 1945
• 
  Raepenburg Castle, home of Count Bernard d'Udekem d'Acoz