Alexander Friedrich Michael Lebrecht Nikolaus Arthur, Graf von Keyserling (August 15, 1815 in Kabile, now Kabile Parish, Kuldiga District, Latvia – May 8, 1891 in Raikküla, now Raikküla Parish, Rapla County, Estonia) was a Baltic German geologist and paleontologist. A member of the Keyserlingk clan, a wealthy aristocratic Baltic German family, he is considered to be one of the founders of Russian geology, making many expeditions on behalf of his close personal friend and friend of the family, Tsar Nicholas I.
He was also a botanist and zoologist who wrote Die wirbelthiere Europa's (Vertebrates of Europe) with Johann Heinrich Blasius. This work was published in 1840.