Princess Henriette of Belgium, was the daughter of Prince Philippe, Count of Flanders, and Princess Marie of Hohenzollern. She was the younger twin sister of Princess Joséphine Marie of Belgium, who died at the age of six weeks in 1871. She was the eldest sister of King Albert I of Belgium.

Prince Philippe of Belgium, Count of Flanders, was the third born and second surviving son of King Leopold I of Belgium and Louise d'Orléans. He was the brother of Leopold II of Belgium and Empress Carlota of Mexico.