Peter Chelcicky or Petr Chelčický (c. 1390 – c. 1460) is a Christian spiritual leader and author in fifteenth century Bohemia (modern Czech Republic).

He is one of the most influential thinkers of the Bohemian Reformation.

His published works concentrate on critique of immorality and violence of the contemporary church and state.

He proposes a number of Bible-based improvements for human society, including nonresistance, which will influence such luminaries as Tolstoy, Gandhi, and M.L.King.

Paradoxically, the main part of the Hussite movement rejects his teachings against nonviolence and avoiding politics, which lead to much violence among the Hussite movement in the end.

Chelcicky's teachings lay the foundation of the Unity of the Brethren.