The Masque of Anarchy is a British political poem written in 1819 by Percy Bysshe Shelley following the Peterloo Massacre of that year.

Shelley begins his poem, written on the occasion of the Peterloo Massacre, Manchester 1819, with the powerful images of the unjust forms of authority of his time, "God, and King, and Law" – and then imagines the stirrings of a radically new form of social action: "Let a great assembly be, of the fearless, of the free".

In his call for freedom, it is perhaps the first modern statement of the principle of nonviolent resistance.