George Parker, 2nd Earl of Macclesfield

George Parker, 2nd Earl of Macclesfield, PRS (c. 1695 or 1697 – 17 March 1764) was an English peer and astronomer.

Styled Viscount Parker from 1721 to 1732, he was Member of Parliament (MP) for Wallingford from 1722 to 1727, but his interests were not in politics. In 1722 he became a fellow of the Royal Society, and he spent most of his time in astronomical observations at his Oxfordshire seat, Shirburn Castle, which had been bought by his father in 1716; here he built an observatory and a chemical laboratory.

He was very prominent in effecting the changeover to the Gregorian calendar, which came into effect in 1752. His action in this matter, however, was somewhat unpopular, as the opinion was fairly general that he had robbed the people of eleven days. When his son ran for parliament as a Whig in 1754, resentment over his role in the calendar reform was one of many issues raised by the son's Tory opponents; a famous 1755 Hogarth painting influenced by the events of these elections is the main historical source for the "Give us our eleven days" slogan.

From 1752 until his death, Macclesfield was president of the Royal Society, and he made some observations on the great 1755 Lisbon earthquake.

In 1750 Macclesfield was offered the honorary position of vice president of the Foundling Hospital, which he accepted and kept until his death in 1764. The Foundling Hospital was a charitable institution created a decade earlier, dedicated to saving London's abandoned children. The Earl seems to have taken his position seriously, as he commissioned the artist Benjamin Wilson to paint a full size portrait of him, which he then donated to the Hospital. The portrait is still in the Foundling Hospital Collection and available to view at the Foundling Museum.

In 1755, Parker was elected a foreign member of the Royal Swedish Academy of Sciences. He also was a corresponding member of the Académie des sciences.