A constituent assembly is a body assembled for the purpose of drafting or revising a constitution. Members of a constituent assembly may be elected by popular vote, drawn by sortition, appointed, or some combination of these methods. A constituent assembly is usually set up for its specific purpose, which it carries out in a relatively short time, after which the assembly is dissolved. Unlike forms of constitution-making in which a constitution is unilaterally imposed by a sovereign lawmaker, the constituent assembly creates a constitution through "internally imposed" actions, in that members of the constituent assembly are themselves citizens, but not necessarily the political leaders, of the country for which they are creating a constitution.

One example of a constituent assembly is the Constituent Assembly of India, which was elected to frame the Constitution of India. It was elected by the Provincial Assembly and its members served as the nations first Parliament as the Provisional Parliament of India. The Constitution of India was drafted by the Constituent Assembly, and it was implemented under the Cabinet Mission Plan on 16 May 1946. The members of the Constituent Assembly were elected by the provincial assemblies by a single, transferable-vote system of proportional representation. The Constituent Assembly of India consisted of indirectly elected representatives and existed for approximately three years.