Lego (/ˈlɛɡoʊ/ LEG-oh, Danish: [ˈle̝:ko];stylized as LEGO) is a line of plastic construction toys manufactured by the Lego Group, a privately held company based in Billund, Denmark. Lego consists of variously colored interlocking plastic bricks made of acrylonitrile butadiene styrene that accompany an array of gears, figurines called minifigures, and various other parts. Its pieces can be assembled and connected in many ways to construct objects, including vehicles, buildings, and working robots. Anything constructed can be taken apart again, and the pieces reused to make new things.

The Lego Group began manufacturing the interlocking toy bricks in 1949. Moulding is done in Denmark, Hungary, Mexico, and China. Brick decorations and packaging are done at plants in the former three countries and in the Czech Republic. Annual production of the bricks averages approximately 36 billion, or about 1140 elements per second.

Films, games competitions, and eight Legoland amusement parks have been developed under the brand. One of Europe's biggest companies, Lego is the largest toy manufacturer in the world by sales.As of July 2015, 600 billion Lego parts had been produced.