The article presents the development of the missionary and educational activities of the Polish clergy in Greece in the 19th and early 20th centuries. During this period, a large number of Polish Jesuits and nuns went to Greece, where they worked in Catholic and Orthodox communities on the Aegean Islands. It is known that Polish priests stayed in Greece since the end of the Middle Ages. At the end of the 18th century, Belarusian Jesuits established contacts with Jesuit missionaries, mainly French and Italian, on the islands of Tinos and Siros. In 1804, Belarusian Jesuits received permission from Pope Pius V to participate in Greek missions. When Greece gained independence in 1830, more Jesuits arrived on the Aegean island. At the turn of the 19th and 20th centuries, even more Polish Jesuits and diocesan priests came to Greece.