Plasticine is a putty-like modelling material made from calcium salts, petroleum jelly and aliphatic acids. Though originally a brand name for the British version of the product, it is now applied generically in English as a product category to other formulations.

Plasticine is used for children's play and as a modelling medium for more formal or permanent structures. Because of its non-drying property, it is a material commonly chosen for stop motion animation, including several Academy Award-winning films by Nick Park.

Franz Kolb, owner of a pharmacy in Munich, Germany, invented an oil-based modelling clay in 1880. At the time, the city was a centre for the arts, and among Kolb's circle of friends were sculptors. They complained about how with the clay they were using for modelling, their sculptures would dry too fast and that, particularly in winter, it was too difficult to work with. In order to commercialize his invention, he presented it to the Faber-Castell company in 1887, which had back then the name "Kunst-Modellierthon" (known as Plastilin), where it is still sold nowadays under the name "Münchner Künstler Plastilin" (Munich artists' Plastilin). In Italy, the product Pongo is also marketed as "plastilina" and shares the main attributes of Plasticine.

Plasticine is approximately 65% bulking agent (principally gypsum), 10% petroleum jelly, 5% lime, 10% lanolin and 10% stearic acid. It cannot be hardened by firing, it melts when exposed to heat, and is flammable at higher temperatures.^{[citation needed]} In France, it is made by Herbin, and marketed as Plastiline. In Spain, toy manufacturer Jovi markets a product also branded "Plastilina", made from vegetable matter which makes it lighter. Play-Doh, which is based on flour, salt and water, dries on exposure to air.

William Harbutt, an art teacher in Bath, England, formulated Plasticine in 1897. Harbutt wanted a non-drying clay for his sculpture students. He created a non-toxic, sterile, soft and malleable clay that did not dry when exposed to air.

Harbutt received a patent in 1899 and commercial production started at a factory in Bathampton in 1900. The original Plasticine was grey, but four colours were produced for initial sales to the public. Plasticine was used by children and was often bought by schools for teaching art. It has found a wide variety of other uses (for example moulding casts for plaster, and plastics).

Harbutt patented a different formulation in 1915, which added wool fibres to give plasticine a stronger composition intended for ear plugs, and as a sterile dressing for wounds and burns. The Harbutt company marketed Plasticine as a children's toy by producing modelling kits based on characters from children's stories, such as Noddy, the Mr. Men and Paddington Bear.

The original Plasticine factory was destroyed by fire in 1963 and replaced by a modern building. The Harbutt company produced Plasticine in Bathampton until 1983, when production was moved to Thailand.