A great power is a nation or state that has the ability to exert its influence on a global scale. Great powers characteristically possess economic, military, diplomatic, and cultural strength, which may cause other, smaller nations to consider the opinions of great powers before taking actions of their own.

The term "great power" was first used to represent the most important powers in Europe during the post-Napoleonic era. Since then, power has been shifted numerous times, most dramatically during the First and Second World Wars. While some nations are widely considered to be great powers, there is no definitive list, leading to a continuing debate.