The Lego Group began in the workshop of Ole Kirk Christiansen (1891–1958), a carpenter from Billund, Denmark, who began making wooden toys in 1932.[7][8] In 1934, his company came to be called "Lego", derived from the Danish phrase leg godt [lɑjˀ ˈkʌt],[9][10] which means "play well".[11] In 1947, Lego expanded to begin producing plastic toys.[12] In 1949 the business began producing, among other new products, an early version of the now familiar interlocking bricks, calling them "Automatic Binding Bricks". These bricks were based on the Kiddicraft Self-Locking Bricks, invented by Hilary Page in 1939 and patented in the United Kingdom in 1940[13] before being displayed at the 1947 Earl's Court Toy Fair.[14] Lego had received a sample of the Kiddicraft bricks from the supplier of an injection-molding machine that it purchased.[15][16][17][18] The bricks, originally manufactured from cellulose acetate,[19] were a development of the traditional stackable wooden blocks of the time.[12]

The Lego Group's motto, "only the best is good enough"[20] (Danish: det bedste er ikke for godt, literally "the best isn't excessively good") was created in 1936.[8] Christiansen created the motto, still used today, to encourage his employees never to skimp on quality, a value he believed in strongly.[8] By 1951, plastic toys accounted for half of the company's output, even though the Danish trade magazine Legetøjs-Tidende ("Toy Times"), visiting the Lego factory in Billund in the early 1950s, wrote that plastic would never be able to replace traditional wooden toys.[21] Although a common sentiment, Lego toys seem to have become a significant exception to the dislike of plastic in children's toys, due in part to the high standards set by Ole Kirk.[22]

By 1954, Christiansen's son, Godtfred, had become the junior managing director of the Lego Group.[21] It was his conversation with an overseas buyer that led to the idea of a toy system. Godtfred saw the immense potential in Lego bricks to become a system for creative play, but the bricks still had some problems from a technical standpoint: Their locking ability was still limited, and they were not yet versatile.[2] In 1958, the modern brick design was developed; ABS subsequently replaced cellulose acetate as the manufacturing material five years later.[19][23][24] A patent application for the modern Lego brick design was filed in Denmark on 28 January 1958 and in various other countries in the subsequent few years.[25][26]

The Lego Group's Duplo product line was introduced in 1969 and became a range of blocks whose lengths measure twice the width, height, and depth of standard Lego blocks and are aimed towards younger children.[21][27] In 1978, Lego produced the first minifigures, which have since become a staple in most sets.[28]

In 1997, more than five million Lego pieces were swept into the sea when a wave hit a cargo ship off the coast of Cornwall, England. Pieces have washed up over the ensuing decades, attracting attention from news outlets and social media.[29]

In May 2011, Space Shuttle Endeavour mission STS-134 brought 13 Lego kits to the International Space Station, where astronauts built models to see how they would react in microgravity, as a part of the Lego Bricks in Space program.[30][31] In May 2013, the largest model ever created, made of over 5 million bricks, was displayed in New York City: a one-to-one scale model of a Star Wars X-wing fighter.[32] Other record breakers include a 34-metre (112 ft) tower[33] and a 4 km (2.5 mi) railway.[34][35]

In February 2015, marketing consulting company Brand Finance ranked Lego as the "world's most powerful brand", overtaking Ferrari.[36][37]

While Lego has generally been considered a children's toy, there have also been adult fans of the toys. In 2020, Lego introduced sets aged at 18+, generally some of their more expensive and difficult-to-assemble sets based on real world or fictional objects, such as the Concorde or Rivendell. The timing of these sets favorably aligned with the COVID-19 pandemic, with many adults purchasing these sets to work on during various lockdown periods. Popularity within adults was further pushed by the release of The Lego Movie and the reality series Lego Masters. By 2024, nearly 15% of the sets released in the U.S. were aimed at adult builders.[38]

In May 2025 Lego announced that it was planning to move its London headquarters from Farringdon to 76 South Bank, in 2027.[39]