In political science, an initiative (also known as a popular initiative or citizens' initiative) is a means by which a petition signed by a certain number of registered voters can force a government to choose either to enact a law or hold a public vote in the legislature in what is called indirect initiative, or under direct initiative, where the proposition is put to a plebiscite or referendum, in what is called a Popular initiated Referendum or citizen-initiated referendum.

In an indirect initiative, a measure is first referred to the legislature, and then put to a popular vote only if not enacted by the legislature. If the proposed law is rejected by the legislature, the government may be forced to put the proposition to a referendum. The initiative may then take the form of a direct initiative or an indirect initiative. In a direct initiative, a measure is put directly to a referendum. The vote may be on a proposed federal level, statute, constitutional amendment, charter amendment or local ordinance, or obligate the executive or legislature to consider the subject by submitting it to the order of the day. It is a form of direct democracy.