Tomorrowland is one of the many "themed lands" featured at all of the Magic Kingdom styled Disney theme parks around the world owned or licensed by The Walt Disney Company. Each version of the land is different and features numerous attractions that depict views of the future. Disneyland Park in Paris includes a similar area called Discoveryland, which shares some elements with other Tomorrowlands but emphasizes visions of the future inspired by Jules Verne.

Walt Disney was known for his futurist views and, through his television programs, showed the American public how the world was moving into the future. Tomorrowland was the realized culmination of his views. In his own words: "Tomorrow can be a wonderful age. Our scientists today are opening the doors of the Space Age to achievements that will benefit our children and generations to come. The Tomorrowland attractions have been designed to give you an opportunity to participate in adventures that are a living blueprint of our future."

Disneyland's Tomorrowland is now in its third generation, and the Magic Kingdom's Tomorrowland is in its second. The Walt Disney Company has mentioned that it wanted to keep Tomorrowland from becoming "Yesterdayland". As a self-referential joke along this line, the 2007 Walt Disney Animation Studios film Meet the Robinsons (which is set mainly in the year 2037) features an amusement park called Todayland, which has rides that look similar to Space Mountain and Disneyland's original Rocket Jets.

A vista into a world of wondrous ideas, signifying Man's achievements... A step into the future, with predictions of constructed things to come. Tomorrow offers new frontiers in science, adventure and ideals. The Atomic Age, the challenge of Outer Space and the hope for a peaceful, unified world.

During the dedication, Walt Disney started speaking, was told that he wasn't yet on air, and then had to restart once the television viewers were watching.

The first Tomorrowland opened at Disneyland on July 17, 1955, with only several of its planned attractions open, due to budget cuts. The construction of the park was rushed, so Tomorrowland was the last land to be finished. It became something of a corporate showcase, despite Walt Disney's reluctance. Monsanto Company, American Motors, Richfield Oil, and Dutch Boy Paint were some of the many companies to open showcases in Tomorrowland in the first few years.

Since the park was on a strict budget, one cost-cutting idea was to reuse the sets of the Nautilus from Disney's 1954 movie 20,000 Leagues Under the Sea as a walkthrough attraction. This remained open until 1966. For the first four years, most of Tomorrowland was generally open space and considered to be very corporate-fueled. However, the area gained more attractions as time passed, many of which have since been removed.

When Disneyland opened, Tomorrowland represented the future in the year 1986.