Sir Thomas Hackett (died 1706) was an Irish Jacobite official and merchant.
He was engaged in foreign trade out of Dublin by 1666, and became a banker to many Old English Roman Catholic families in Ireland.
In October 1687, he was knighted and appointed Lord Mayor of Dublin by James II of England.
[1] The Jacobite defeat in Ireland in 1690 resulted in Hackett being outlawed and most of his properties were seized.
In 1694 he had a pass to go to the Dutch Republic, where his activities were monitored by English government officials who believed him to be an agent of the Jacobite court in exile at Château de Saint-Germain-en-Laye.