regent

upright=1.35|thumb|16th century Swedish regent Sten Sture the Younger|Stenonis Sture and wife [[Christina Gyllenstierna who both operated in strong resistance to Danish rule during the Kalmar Union]] upright=1.35|thumb|The oath of the provisional triumvirate|triumviral regents of the [[Empire of Brazil on behalf of the 5-year-old Emperor Pedro II in 1831, at the beginning of the Regency period.]] In a monarchy, a regent () is a person appointed to execute the office of a monarch temporarily, essentially as a substitute ruler. Regencies may arise for a number of reasons, including the monarch being a minor, ill, absent from the country, or otherwise unavailable. A regent may also be appointed in cases where the throne is vacant, or the identity of the legitimate monarch is disputed.

The rule of a regent or regents is called a regency. A regent or regency council may be formed as an ad hoc measure, or there may be a formal and regular appointment process. Regent in some countries has also been used as a formal title granted to a monarch's most trusted advisor or personal assistant. If the regent is holding the position due to their being in the line of succession, the compound term prince regent is often used; if the regent of a minor is their mother, and she is wife or widow of a king, she would be referred to as queen regent.