The 1719 Instrument of Government (Swedish: regeringsform) adopted on 21 February 1719 by the Riksdag of the Estates (Swedish parliament), was the constitution of the Kingdom of Sweden from 1719 to 1720. Although only in force for a few months, it has great significance in Swedish history, as its promulgation marked the end of the country's first period of absolutism (1680-1719) and the beginning of the period of constitutional monarchy and parliamentary government traditionally known as the Age of Liberty.

The Instrument came about as a result of the succession crisis which occurred after Charles XII of Sweden died childless during the Great Northern War, leaving two potential heirs: his sister Ulrika Eleonora the Younger, and his nephew Charles Frederick, Duke of Holstein-Gottorp.^{[1][page needed]} The crisis was eventually resolved by a deal whereby the Riksdag acknowledged Ulrika as queen regnant, and in exchange she signed a new constitution, thereby renouncing the absolute monarchy instituted by her father King Charles XI.^{[2][page needed]} As such it was in effect a revival of the Instrument of Government (1634), and indeed the title "Instrument of Government" (Swedish: regeringsform) was deliberately chosen to invoke that earlier document;^[3] there are however substantial differences between the two, with the 1634 Instrument having a more narrowly descriptive and administrative function while the 1719 Instrument was explicitly intended to be a political constitution in the modern sense.^[4]

Only a year after its promulgation, the 1719 Instrument of Government was replaced by a new constitution, the Instrument of Government (1720), although the two were largely identical in content.^[5] The 1720 Instrument subsequently remained in force for the rest of the Age of Liberty, until absolutism was restored by King Gustav III's self-coup in 1772.