Alexander Alexandrovich Elenkin (1873–1942, Russian: ???????, ????????? ?????????????) was a Russian lichenologist.
He was born in Warsaw and took his degree in Botany at the University of Warsaw, graduating in 1893.
He became an assistant there in 1898.
The next year he became conservator and director of the Cryptogamic Department at the Imperial Botanic Garden of St Petersburg.
In 1931 the Botanic Garden was merged into the Botanical Institute and he became a professor there.
He is known as the "father of Russian lichenology" and wrote many works on the subject.
He died in Russia, either in Kazan or St Petersburg.The standard author abbreviation Elenkin is used to indicate this person as the author when citing a botanical name.