Isaac Thomas Cookson (1817–1881) was a 19th-century Member of Parliament in Canterbury, New Zealand.
He represented the Christchurch Country electorate in 1860 following the resignation of John Ollivier, and then the Kaiapoi electorate from 1861 to 1863, when he resigned.
He was a member of the Canterbury Provincial Council and represented the Town of Lyttelton electorate (1853–1861) and then the City of Christchurch electorate (1861–1862).