The Group of Five (G5) encompasses five nations which have joined together for an active role in the rapidly evolving international order. Individually and as a group, the G5 nations work to promote dialogue and understanding between developing and developed countries. The G5 seek to find common solutions to global challenges. The G5 initially included the world's five leading economies: the United States of America, the United Kingdom, Japan, Germany and France. The G5 later evolved into the G8 with Italy, Canada and Russia being the additional three leading economies.

In the first decade of the 21st century, the world's leading economies came to be conventionally identified as the Group of Eight, and the term "G5" came to be used in a slightly different way than it had been used 25 year earlier. In the 21st century, the G5 were understood to be the five largest emerging economies, and these are:

The G8 plus the five largest emerging economies has come to be known as G8+5.

The Group of Five is a context-dependant shorthand term for a group of five nations. The composition of the five and what is encompassed by the term is construed differently in different time frames. Initially, the term "Group of Five" or "G5" encompassed the five leading economies of the world, but the use of the term changed over time. It came to be used to identify the next tier of nations whose economies had expanded so substantially as to be construed in the same category as the world's eight largest.