Ostap () is a Ukrainian male given name. It derives from the Greek name Eustathius.
People with this name include:
Ostap Bender, a fictional character from the Russian novel The Twelve Chairs Ostap Dashkevych (ca. 1495–1535), commander of the Ukrainian Cossacks Ostap Ortwin (1876–1942), Polish journalist Ostap Steckiw (1924–2001), Polish-born Canadian soccer player Ostap Veresai (1803–1890), Ukrainian minstrel Ostap Vyshnya (1889–1956), Ukrainian writer, satirist, and medical official