Dmytro Ivanovych Yavornytsky or Dmitry Ivanovich Yavornitsky (Ukrainian: Дмитро́ Іва́нович Яворни́цький, Russian: Дмитрий Иванович Яворницкий) (November 6, 1855, Kharkov Governorate, Russian Empire – August 5, 1940, Dnipropetrovsk, Soviet Union) was a Russian, Ukrainian and Soviet academician, historian, archeologist, ethnographer, folklorist, and lexicographer. Yavornytsky was a member of Moscow Archaeological Society (from 1885), of St. Petersburg Russian Archaeological Society (from 1886) and academician of Ukrainian Academy of Sciences (from 1929).
He was one of the most prominent researchers of the Zaporozhian Cossacks from the time of the Hetmanate, and the author of their first general history. In recognition of his many contributions to the preservation of Zaporozhian history and culture, he is widely known as "the father of the Zaporozhians".
Yavornytsky was educated at Kharkov University, Kazan, and Warsaw universities but his academic career was repeatedly interrupted for political reasons. Both as a student and later as a teacher, he was wrongly accused of "Ukrainian separatism" and dismissed from his position. In the 1890s, he was compelled to go to Russian Turkestan in order to find employment. In 1897, the Russian historian Vasily Klyuchevsky helped him to obtain a position as lecturer on the Zaporozhian Cossacks at Moscow University. In 1902, when he was offered a position as Director of the Ekaterinoslav Historical Museum in modern-day central Ukraine, he gladly accepted and remained there to the end of his life.