Oskar Kallas

13 October] 1868 in Kirikuküla, Saaremaa – 26 January 1946 in Stockholm)[citation needed] was an Estonian diplomat, linguist and folklorist.

Together with his friend Jaan Tõnisson, who later became a politician and Estonian head of state, he was involved in the nationalist student association Eesti Üliõpilaste Selts.

At that time, together with Jaan Tõnisson, Kallas founded the prestigious newspaper Postimees which opposed the Russification in Estonia.

While studying at the University of Helsinki, Kallas came in contact with the folklorist Kaarle Krohn, under whose guidance he wrote his doctoral thesis (which he defended in 1901).

In 1909 Kallas was one of the founders of the Estonian National Museum (Eesti Rahva Muuseum) in Tartu and was a volunteer department head for many years.