Count Grigory Kirillovich Razumovsky (November 10, 1759 – June 3, 1837) was a Ukrainian nobleman, political philosopher, botanist, zoologist and geologist known from his writings in the West as Gregor or Grégoire, who lost his Russian citizenship for openly criticizing the czarist system under emperor Alexander I, which he saw as pandering to the desires of a corrupt oligarchy of nobles. Gregor emigrated to western Europe, where was subsequently incorporated into the Bohemian nobility (Inkolat im Herrenstande) in 1811 and accorded the rank of count of the Austrian Empire. As a natural scientist, Gregor was the first to describe and classify Lissotrion helveticus. He was the fifth son of the last hetman of Ukraine, Kirill Grigorievich Razumovsky and brother of prince Andreas Razumovsky, he is also the ancestor of all living members of the family as such, the Russian lines having gone extinct by
He was the author of "Anecdotes et pensées philosophiques sur la Russie" (?) and of Observations Minéralogiques sur les environs de Vienne (1822).
In 1788, he was elected a foreign member of the Royal Swedish Academy of Sciences.