Isaac Halstead Williamson (September 27, 1767 – July 10, 1844) was an American lawyer, jurist, and politician who served two terms as the eighth governor of New Jersey, from 1817 to 1829.

In 1808, he married Anne Crossdale Jouet (1777–1853) and together they had two sons, Benjamin in 1809 and Isaac Halstead in 1811.

As part of his duties as governor, Williamson served as the judge of the Prerogative Court of New Jersey.

In 1844, he was unanimously elected to be President of the convention that framed the revised New Jersey State Constitution.

His collection of the Chinese Export Armorial Porcelain dinnerware that belonged to his wife's family and bears the Jouet coat-of-arms, is archived at the New Hope, Pennsylvania Historical Society.