Bartholomeus de Ligt (17 July 1883, Schalkwijk, Utrecht – 3 September 1938, Nantes) was a Dutch anarcho-pacifist and antimilitarist. He is chiefly known for his support of conscientious objectors.
His father was a Calvinist pastor. Following in his father's footsteps, he became a theology student at the University of Utrecht. While there, he was exposed to liberal thinking and Hegelian philosophy for the first time and, in 1909, became a member of the League of Christian Socialists. In 1910, he was appointed pastor of the Reformed Church at Nuenen, near Eindhoven in Brabant where van Gogh's father had been pastor 25 years before.
In 1914, de Ligt joined with fellow pastors A. R. de Jong and Truus Kruyt to write "The Guilt of the Churches", charging that the Christian establishment had been complicit in the events that produced World War I. Afterwards, all of his writings became forbidden literature for the Dutch armed forces. His impassioned sermons in support of conscientious objection resulted in his being banned from those parts of the Netherlands considered to be in the war zone.
In 1918 he resigned as pastor declaring that, because of his increasingly universalist approach to religion, he no longer considered himself to be specifically a Christian.
In 1918, De Ligt married the Swiss activist Catherina Lydia van Rossem, with whom he had a son. He was imprisoned in 1921 for organizing a general strike to gain the release of Herman Groenendaal, a jailed conscientious objector who had gone on a hunger strike. Later that year, he founded the IAMB (International Anti-Militarism Bureau). As he was becoming more involved with the work of the League of Nations, in 1925 he moved to Geneva, where he remained for the rest of his life. However, De Ligt became sceptical about the League's efforts, viewing it as how the colonial powers maintained an unjust world order. De Ligt instead regarded the Brussels Congress Against Colonial Oppression and Imperialism, held in 1927 as more representative of the world's population. At a meeting of the War Resisters International in 1934, he presented his now-famous "Plan of a Campaign Against All Wars and Preparation for War". (The full text of which may be found in The Conquest of Violence.) De Ligt also took a firm stand against fascism and Nazism in the 1930s. During the 1930s, De Ligt also promoted the ideas of Simone Weil.