(February 9, 1862 – August 8, 1937) was an American specialist on Indo-European languages.

After studying at the University of Halle from 1887 to 1889 he became an adjunct professor of English language and literature.

In 1901, during a visit to India and Ceylon, he received special attention from the Parsees, who presented to Columbia a valuable collection of Zoroastrian manuscripts in recognition of the instruction there given by him in their ancient texts.

Jackson's grammar of Avestan, the language used in the Zoroastrian scriptures, is still considered to be the seminal work on the topic.

[1] He made many contributions to the Journal of the American Oriental Society.