Political corruption is the use of legislated powers by government officials for illegitimate private gain. Misuse of government power for other purposes, such as repression of political opponents and general police brutality, is not considered political corruption. Neither are illegal acts by private persons or corporations not directly involved with the government. An illegal act by an officeholder constitutes political corruption only if the act is directly related to their official duties.

All forms of government are susceptible to political corruption. Forms of corruption vary, but include bribery, extortion, cronyism, nepotism, patronage, graft, and embezzlement. While corruption may facilitate criminal enterprise such as drug trafficking, money laundering, and trafficking, it is not restricted to these organized crime activities. In some nations, corruption is so common that it has gained normative status. The end point of political corruption is a kleptocracy, literally "rule by thieves".

The activities that constitute illegal corruption differ depending on the country or jurisdiction. Certain political funding practices that are legal in one place may be illegal in another. In some countries, government officials have broad or poorly defined powers, and the line between what is legal and illegal can be difficult to draw.

Bribery around the world is estimated at about $1 trillion (£494bn), and the burden of corruption falls disproportionately on the bottom billion people living in extreme poverty.