Countess Stéphanie de Lannoy was born on February 18, 1984 at Ronse, Belgium, the youngest of eight children of Count Philippe de Lannoy Alix della Faille de Leverghem. She grew up at the family's estate, Chateau d'Anvaing, in Hainault. Her parents also have a residence in Brussels.
The young countess began her education at a Dutch language primary school, Sancta Maria in Ronse. She later spent two years at College Saint-Odile in the north of France, before returning to Belgium to study at the Institut de la Vierge Fidele in Brussels. She graduated in 2002.
After graduation, at the age of 18, she traveled to Moscow for one year, where she took classes in Russian and Russian literature. She also continued studying the violin.
Stéphanie received a degree in German Philology from the Catholic University in Louvain. She continued her education in Berlin, earning a master's degree. Her thesis was on German influence on Russian Romanticism.
She also worked for the Belgian embassy in Berlin in the department for Walloon exports. She returned to Belgium, and found a job in an investment company.
She loves classical music and has studied music theory, and she can play the piano and violin. She also enjoys reading and learning foreign languages. Her mother tongue is French, but she is also fluent in German and English.
Countess Stéphanie enjoys skiing and swimming.
One of Stéphanie's first cousins, Countess Christine de Lannoy is married to Count Bruno de Limburg-Stirum, son of Princess Helene of France. A more distant cousin, Countess Minthia, is married to Prince Lamoral de Ligne, youngest son of Princess Alix of Luxembourg.