The Lego company, led by Ole Kirk Christiansen, introduced plastic toys alongside their existing wooden toy line in 1949 after purchasing one of the first injection moulding machines in 1947.: 10  One son, Godtfred Kirk Christiansen (GKC), was named the managing director of the family business in 1957 shortly before his father died and just two years later he bought out his three brothers.: 20  In the 1960s, GKC decided to open a 14-acre (5.7 ha) Legoland Park adjacent to the Lego factory in Billund to promote his toy business; the factory itself was already drawing approximately 20,000 visitors per year by the mid-1960s, who came to view models produced for trade shows and shops.: 49   GKC hired Arnold Boutrop as the park's first general director and designer; after visiting Madurodam, the two men began finalizing plans for what would become Miniland, the main attraction of Legoland.: 49  Dagny Holm, a cousin of GKC trained as a sculptor who was hired as a model designer in 1961 is credited with much of the original design and building of Miniland.: 50  The park became an instant success, with 625,000 visitors in its first abbreviated season after opening on 7 June 1968.: 56 

Over the years, Legoland Billund has added many original models and rides. The park, which has now been expanded to cover 45 acres (18 ha), is divided into nine themed areas, including Duplo Land, Imagination Zone, LEGOREDO Town, Adventure Land, Lego City, Knight's Kingdom, Mini Land, Pirate Land, and Polar Land.

Today, Legoland Billund is the most visited tourist attraction in Jutland and the third-most visited attraction in Denmark, after Tivoli Gardens and Dyrehavsbakken. Several other Legolands have since been built in other parts of the world:

The Blackstone Group, an investment firm, bought a 70% controlling stake in Legoland in 2005, with the remaining 30% still owned by Lego. The parks are operated by Merlin Entertainments.

On 29 May 2024, a fire suspected to have been caused by a short circuit inside an electric rail car that was being charged overnight erupted at the park's Miniland attraction, destroying several replicas of famous buildings and a model of a traditional Danish port.