The Universal Century is the world view on which the Mobile Suit Gundam series is based. The year that settlers begin emigrating to orbiting space colonies is designated as "Universal Century 0001," the start of a new era that replaces the modern-day "Anno Domino" (AD). Subsequent Gundam works use this timeline as the basis for their own eras.

Within the Universal Century world, the animated works begin with "Mobile Suit Gundam" in U.C. 0079, and extend through "Mobile Suit V Gundam" in U.C. 0153.

In the Universal Century, overpopulation of Earth led to food shortages and the destruction of the environment. To counter this, numerous space colonies were built throughout the so-called "Earth sphere," and an aggressive program of space emigration was pursued. The colonies became a new homeland for much of humanity, and people gave birth to children, raised families, and died there.

Half a century later, friction developed between the Earth Federation government and the colony residents over the question of autonomy for the space colonies.

In U.C. 0079 the colony group furthest from the earth, Side 3, now calling itself the Principality of Zeon, declared a war of independence against the Earth Federation.

Here began a legacy of unending warfare between the space colonists (spacenoids) and those living on Earth (earthnoids).