Robert Myddleton (1678–1733), of Chirk Castle, Denbighshire, was a British lawyer and politician who sat in the House of Commons from 1722 to 1733.
Myddleton was baptized on 14 June 1678, the eldest surviving son of Richard Myddelton of Shrewsbury and Crutched Friars, London.
When his uncle Sir Richard Myddelton, Bt died in 1716, he stood for Denbighshire on the Chirk Castle interest at the ensuing by-election on 30 June 1716, but was defeated by Watkin Williams.
He asked the Administration to arrange for the Denbighshire election to precede that for Denbigh Boroughs so that if he were defeated for the former he could be returned for the latter.
He voted with the Tories against the Government, even joining his opponent, Watkin Williams Wynn, in opposing a loyal address from the county on the Atterbury plot.