The Dönme were a group of Sabbatean crypto-Jews in the Ottoman Empire who converted outwardly to Islam, but retained their Jewish faith and Kabbalistic beliefs in secret. The movement was centered mainly in Thessaloniki. It originated during and soon after the era of Sabbatai Zevi, a 17th-century Sephardic Jewish Rabbi and Kabbalist who claimed to be the Jewish Messiah and eventually feigned conversion to Islam under threat of death from the Sultan Mehmed IV. After Zevi's forced conversion to Islam, a number of Sabbatean Jews purportedly converted to Islam and became the Dönme. Some Sabbateans lived on into 21st-century Turkey as descendants of the Dönme.

The Sabbateans were a variety of Jewish followers, disciples, and believers in Sabbatai Zevi (1626–1676), a Sephardic Jewish rabbi and Kabbalist who was proclaimed to be the Jewish Messiah in 1666 by Nathan of Gaza.