Colonization is a trilogy of books written by Harry Turtledove. It is a continuation of the situation set up in the Worldwar four-book series, projecting the situation between humanity and the Race (the bipedal lizardlike invaders and settlers from Worldwar) nearly twenty years forward into the mid-1960s.

The Race has settled and plans to colonize nearly half the surface of the Earth. This half includes Africa, Australia, China, southern Asia, Central America, and South America. The United States, the Soviet Union, the Greater German Reich (Germany and the territories it occupied during World War II), Britain, and Japan are the other major powers when the Race's colonization fleet of eighty to one hundred million settlers arrives. Humanity and the Race still jockey for advantages over each other.

Books of the Colonization trilogy are:

• Colonization: Second Contact (1999)
• Colonization: Down to Earth (2000)
• Colonization: Aftershocks (2001)

A follow-up novel to this series, Homeward Bound, was released in 2004. It begins in 1972, then flashes forward to 1977, 1984, 1994, and finally to 2031 when the American starship Admiral Peary arrives at Tau Ceti and Home, the homeworld of the Race.