Pierre Jacques François de Decker (1812 - 4 January 1891) was a Belgian statesman and author.

He was educated at a Jesuit school, studied law at Paris, and became a journalist on the staff of the Revue de Bruxelles . In 1839 he was elected to the Belgian lower chamber , where he gained a great reputation for oratory. In 1855 he became minister of the interior and prime minister, and attempted, by a combination of the moderate elements of the Catholic and Liberal parties, the impossible task of effecting a settlement of the educational and other questions by which Belgium was distracted.

In 1866 he retired from politics and went into business, with disastrous results. He became involved in financial speculations which lost him his good name as well as the greater part of his fortune; and, though he was never proved to have been more than the victim of clever operators, when in 1871 he was appointed by the Catholic cabinet governor of Limburg, the outcry was so great that he resigned the appointment and retired definitively into private life. He died in 1891.

Decker, who was a member of the Belgian academy , wrote several historical and other works of value, of which the most notable are:

• Etudes historiques et critiques sur les monts-de-pi~t en Belgique (Brussels, 1844)
• De l'influence du libre arbitre de l'homme sur les fails sociaux (1848)
• LEspr-it de parti et lesprit national (1852)
• Etude politique sur le vicomte Ch. Vilain Xliii (1879)
• Episodes de lhist. de lart en Belgique (1883)
• Biograp/zie de H. Conscience (1885)