| Honorific Prefix: | The Right Honourable |
| Thomas Micklethwaite | |
| Constituency Mp: | Arundel |
| Term Start1: | 1715 |
| Term End1: | 1718 |
| Order2: | Treasurer to the Commissioners of Transport |
| Term Start2: | 1708 |
| Term End2: | 1715 |
| Order3: | Lords Commissioner of the Treasury |
| Term Start3: | 1717 |
| Term End3: | 1718 |
| Birth Date: | 1678 |
| Death Date: | 28 March 1718 |
| Mother: | Constance Micklethwaite (nee Middleton) |
| Father: | Joseph Micklethwaite |
| Relatives: | Joseph Micklethwaite, 1st Viscount Micklethwaite (brother) |
Thomas Micklethwaite (1678 – 28 March 1718) was a British MP who served as the Lord Commissioner of the Treasury from 1717 to 1718.
Micklethwaite was born in 1678 and was baptised on 19 July at Holy Trinity Church, Micklegate, he was the first son of Joseph Micklethwaite and Constance Middleton, and the brother of Joseph Micklethwaite, 1st Viscount Micklethwaite. He studied at, but did not graduate from, Jesus College, Cambridge. In 1708, he was appointed Treasurer to the Commissioners of Transport. In 1717 he was made Lord Commissioner of the Treasury after he predecessor Stanhope became first lord and Chancellor of the Exchequer. In 1718, he was appointed Lieutenant-General of the Ordnance. He died on 28 March, 1718.