The Prince (Italian: Il Principe [il ˈprintʃipe]; Latin: De Principatibus) is a 16th-century political treatise written by the Italian diplomat, philosopher, and political theorist Niccolò Machiavelli in the form of a realistic instruction guide for new princes. As a remarkable general theme, The Prince appears to take it for granted that immoral acts are justified if they can help achieve political glory.

From Machiavelli's correspondence, a version was apparently being written in 1513, using a Latin title, De Principatibus (Of Principalities). However, the printed version was not published until 1532, five years after Machiavelli's death. This was carried out with the permission of the Medici pope Clement VII, but "long before then, in fact since the first appearance of The Prince in manuscript, controversy had swirled about his writings".

Although The Prince was written as if it were a traditional work in the mirrors for princes style, it was generally agreed as being especially innovative. This is partly because it was written in the vernacular Italian rather than Latin, a practice that had become increasingly popular since the publication of Dante's Divine Comedy and other works of Renaissance literature. Machiavelli illustrates his reasoning using remarkable comparisons of classical, biblical, and medieval events, including many seemingly positive references to the murderous career of Cesare Borgia, which occurred during Machiavelli's own diplomatic career.