The regulative principle of worship is a Christian theological doctrine teaching that the public worship of God should include those and only those elements that are instituted, commanded, or appointed by command or example in the Bible; that what God institutes in Scripture everything he requires for worship in the Church, and everything else is prohibited.

The regulative principle is often contrasted with the normative principle of worship, which teaches that whatever is not prohibited in Scripture is permitted in worship, so long as it is agreeable to the peace and unity of the Church. In other words, there must be agreement with the general practice of the Church and no prohibition in Scripture for

The normative principle of worship is the generally accepted approach to worship practiced by the Eastern Orthodox, Roman Catholics, Lutherans, Anglicans and Methodists. The regulative principle of worship is generally practiced by the conservative Reformed churches and in other conservative Protestant denominations, and it finds expression in confessional documents such as the Westminster Confession of Faith and the London Baptist Confession of Faith.

Some groups reject the use of musical instruments in worship on this ground . Such groups may argue that there is no example of musical instruments for worship in the New Testament, and/or that the Old Testament uses of instruments in worship were specifically tied to the ceremonial laws of the Temple in Jerusalem (like the Old Testament sacrificial system), and are not applicable in the church. Many early Calvinists eschewed musical instruments in worship, and this practice typified Presbyterians, and other Reformed and Calvinist churches. In recent times, since the 1800s, most of these churches no longer exclude instruments.