A legislator (or lawmaker) is a person who writes and passes laws, especially someone who is a member of a legislature. Legislators are usually politicians and are often elected by the people. Legislatures may be supra-national (for example, the United Nations General Assembly), national (for example, the United States Congress), regional (for example, the Scottish Parliament) or local (for example, local authorities).

The political theory of the separation of powers requires legislators to be different individuals from the members of the executive and the judiciary. Certain political systems adhere to this principle, others do not. In the United Kingdom, for example, the executive is formed almost exclusively from legislators (members of Parliament) although the judiciary is mostly independent (until reforms in 2005, the Lord Chancellor uniquely was a legislator, a member of the executive (indeed, the Cabinet), and a judge).

In continental European jurisprudence and legal discussion, "the legislator" (le législateur) is the abstract entity that has produced the laws. When there is room for interpretation, the intents of the legislator will be questioned, and the court is supposed to rule in the direction that it judges to fit the legislative intent the best — which can be uneasy, in the case of conflicting laws or constitutional provisions.