Joseph Micklethwaite, 1st Viscount Micklethwaite

Joseph Micklethwaite, 1st Viscount Micklethwaite (ca. 1680 – 16 January 1734) was an English politician, peer and diplomat.

Joseph Micklethwaite was born circa 1680. His elder brother was Thomas Micklethwaite of Swine, Yorkshire, who represented Arundel in Parliament, was later a Lord of the Treasury, and subsequently was named Lieutenant-General of the Ordnance. The Micklethwaites were the descendants of Dr. Joseph Micklethwaite of York, who had retired from his physician's practice and had purchased the manor of Swine, becoming a gentleman farmer and an active county magistrate. Dr. Micklethwaite was married to Ann Topham, the widow of Christopher Topham, member of Parliament and York merchant, and the daughter of Percival Levett, a Sheriff of York and a merchant.

Micklethwaite began his career as secretary to Earl Stanhope, the English ambassador to Spain. On 14 August 1724, he was created Baron Micklethwaite, of Portarlington, in the Peerage of Ireland. On 6 June 1727, he was further created Viscount Micklethwaite, of Longford, in the same peerage. Lord Micklethwaite represented the town of Arundel in Parliament in 1727, and in 1732 he represented Hull, in his native Yorkshire, in Parliament.

Lord Micklethwaite died unmarried in 1734 and his titles became extinct.