Kadızade Mehmed Efendi, aka Küçük (Little) Kadızade or Kadızadeli (1582 Balıkesir Province, Ottoman Empire - 1635) was an Islamic preacher in the Ottoman Empire. Those who accepted his ideas called themselves Kadızadeliler ("those for Kadızade").
The Kadızadelis were acting politically by to influencing people. Those preachers that were addressing to the people could criticise the state as they wish and could cause a rebellion. One of the first and exceptional leader of the Kadızade was Kadızade Mehmed Efendi. When he was young, he tried to enroll to a tariqa, but as he found out that he objected to their thinking, he decided to become a preacher.
As his rhetoric was strong, he became famous in a short time and was designated to the Hagia Sophia Mosque as a preacher in 1631, where he pointed to disorders in state affairs. He told that all of these disorders were the result of acting against Sharia. He moved the public against sects that he decided to be contrary to Shariah. He supported the tobacco ban of Murad IV (reigned 1623–1640). As he was reminded that coffee and tobacco is not banned by God, he has said that the prohibition of the ruler suffices. The Kadızades caused the decline in Ottoman education system, and science became conservative.