The Woman's Peace Party (WPP) was an American pacifist and feminist organization formally established in January 1915 in response to World War I. The organization is remembered as the first American peace organization to make use of direct action tactics such as public demonstration. The Woman's Peace Party became the American section of an international organization known as the International Committee of Women for Permanent Peace later in 1915, a group which later changed its name to the Women's International League for Peace and Freedom.

Pacifism is the opposition or resistance to war, militarism or violence. The word pacifism was coined by the French peace campaigner Émile Arnaud and adopted by other peace activists at the tenth Universal Peace Congress in Glasgow in 1901. A related term is ahimsa, which is a core philosophy in Indian religions such as Hinduism, Buddhism, and Jainism. While modern connotations are recent, having been explicated since the 19th century, ancient references abound.