The Prince is a 16th-century political treatise by the Italian diplomat and political theorist Niccolo Machiavelli. Although it was written as if it were a traditional work in the mirrors for princes style, it is generally agreed that it was especially innovative. The Prince is sometimes claimed to be one of the first works of modern philosophy, especially modern political philosophy, in which the effective truth is taken to be more important than any abstract ideal. It was also in direct conflict with the dominant Catholic and scholastic doctrines of the time concerning how to consider politics and ethics.

Although it is relatively short, the treatise is the most remembered of Machiavelli's works and the one most responsible for bringing the word "Machiavellian" into usage as a pejorative. It also helped make "Old Nick" an English term for the devil, and even contributed to the modern negative connotations of the words "politics" and "politician" in western countries. The descriptions within The Prince have the general theme of accepting that the aims of princes—such as glory and survival—can justify the use of immoral means to achieve those ends.