The House of Flanders, also called the Baldwins (Latin: Balduini, French: Baudouinides), was a medieval ruling family of Frankish origin that was founded by Baldwin Iron Arm, son-in-law of Charles the Bald.

The House of Flanders was the first dynasty to transform a county function of the Carolingian Empire into a hereditary fiefdom, the County of Flanders, falling under West Francia, created by the Treaty of Verdun in 843.

The dynasty established the Latin Empire of Constantinople during the Fourth Crusade, and it also briefly ruled the County of Namur (1188–1212).

The House of Flanders became extinct in 1280 with the death of Margaret II.

Members of this house joined the First Crusade, established the Kingdom of Jerusalem, and produced its first kings.