Adolph Ludvig Ribbing, later called Adolph de Leuven (10 January 1765 in Stockholm – 1 April 1843 in Paris), was a Swedish count and politician. He participated in the regicide of Gustav III of Sweden in 1792.
Adolph Ribbing was the son of count Fredrik Ribbing and Eva Helena Löwen. He spent his childhood at the Swedish royal court, as his mother was a popular socialite and the personal friend of both Louisa Ulrika of Prussia and Gustav III of Sweden. He received a military education in Berlin and Paris and became a member of the Life Guards.
In the 1780s, Ribbing came in conflict with the monarch, Gustav III, partially under influence of the ideas then popular in France. His animosity was nurtured when Charlotta Eleonora De Geer, with whom he was in love, was matched by the king with count Hans Henrik von Essen. The engagement was widely disapproved of within the court because of sympathy with the popular Augusta von Fersen, to whom von Essen had been a long term lover, and Ribbing challenged von Essen to a duel. Ribbing injured von Essen in the duel, which took place in 1788. The duel caused a scandal and was regarded as a crime against the king. Ribbing was commandeered to serve at the Vaxholm Castle, which he regarded as an insult and therefore left service.
He took part in the parliamentary sessions of 1789, and became acquainted with Claes Fredrik Horn and Jacob Johan Anckarström in 1792. Ribbing is regarded to have taken a leading role in the planning of the regicide of Gustav III. He was present at the masquerade ball where the assassination took place, but did not take part in it physically. He was pointed out by his accomplices, arrested and made a full confession. Ribbing was sentenced to death in May 1792 and deprived of his rank as a noble, but was pardoned and exiled. He spent the majority of his exile in France under the name de Leuven and was active as a writer. He was at one point the lover of Germaine de Staël. He married Adèle Billiard d'Aubigny in 1799. He was the father of Adolphe de Leuven.