Hereditary Grand Duchess Stéphanie was born on 18 February 1984 in Ronse, Belgium.

Stéphanie is the youngest daughter of the later Countess Alix and the late Count Philippe de Lannoy.

She married Hereditary Grand Duke Guillaume of Luxembourg on 20 October 2012.

Countess Stéphanie de Lannoy is the youngest of eight siblings.