Pierre (Pieter) Jacques François de Decker (1812 – 4 January 1891) was a Belgian Roman Catholic politician, 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. He was a member of parliament from 1839 to 1866.