[2] Initially launched in 1969,[2] the Duplo range has expanded since then to include sets with figures, animals, cars, houses, and trains.

In 1968, second-generation owner Godtfred Kirk Christiansen provided the idea of hollowing out the studs on the Duplo bricks to make them compatible with the system.

In the product catalogue for 1971, the sets were described as being for children from 1 to 2 years but were still sold mixed with Lego bricks, normally designed for ages 3 to 12.

Small figures the size of two-by-two bricks were introduced, made up of a cylindrical head and a tapered, limbless body, similar in design to Fisher-Price's Little People.

These figures have moveable heads, arms, and legs and look like large Lego minifigures, but cannot be taken apart, making them safer for small children.

In 1992, Duplo Toolo was introduced, which was a range of construction sets using screwdrivers and was aimed at children between the ages of three and six.

[7] Lego has made Duplo sets licensed with Bob the Builder and Thomas & Friends characters.

[8] Csaba Tóth, Communications Director, commented, "Every year, about 14 million Duplo boxes come out of the Nyíregyháza factory.

They reappear in the 2019 sequel, The Lego Movie 2: The Second Part, as the same alien invaders, with the story picking up from the events of the previous film.

[12] In October 2019, Lego Duplo World was launched, which is an educational game app that was designed to help children between the ages of two and five reach their key learning goals.

[13] In 2009, Feeding Zoo (set number: 5634) was awarded "DreamToys" in the Construction category by the Toy Retailers Association.

(set number: 10910) was awarded "DreamToys" in the Trains, Planes and Automobiles category by the Toy Retailers Association.