Thomas Dunham Whitaker (1759–1821) was an English clergyman and topographer.
Born at Raynham, Norfolk, on 8 June 1759, he was the son of William Whitaker (1730–1782), curate of Raynham, Norfolk, and his wife Lucy, daughter of Robert Dunham, and widow of Ambrose Allen. In 1760 his father moved to his ancestral house at Holme, in the township of Cliviger, Lancashire, and the boy was in November 1766 placed under the care of the Rev. John Shaw of Rochdale. In November 1774, after spending a short time with the Rev. William Sheepshanks of Grassington in Craven, he was admitted to St John's College, Cambridge, and went into residence in October 1775. He took the degree of LL.B. in November 1781. His intention to enter the legal profession changed on the death of his father in the following year, when he settled at Holme.
He was ordained in 1785, but remained without pastoral charge until 1797, when he was licensed to the perpetual curacy of Holme, where he had rebuilt the chapel at his own cost in 1788. He completed his degree of LL.D. in 1801. In 1809 he became vicar of the extensive parish of Whalley, Lancashire. The rectory of Heysham, near Lancaster, was presented to him in January 1813. He resigned it in 1819. On 7 November 1818 he became vicar of Blackburn, a benefice he retained, together with Whalley, until his death.
When settled at Holme he instituted a local literary club. He had influence with the people of his parishes, and on several occasions exerted it to quell disturbances, particularly at Blackburn in 1817. For his 'patriotic services' he was presented with a public testimonial in April 1821. He was also very interested in topography and forestry, writing books on the subjects. In 1818 he was elected a Fellow of the Royal Society as "a Gentleman well versed in various Branches of Natural Knowledge being desirous of becoming a Fellow of the Royal Society"