Rotational moulding, also known as rotomoulding, is a molding  process for creating many kinds of mostly hollow items, typically of plastic.

A heated mold causes the material within to melt and form a puddle at the bottom of the mold cavity. The mold is then slowly rotated (usually around two perpendicular axes) causing the melted material to flow and stick to the walls of the mold. In order to maintain even thickness throughout the part, the mold continues to rotate during the cooling phase. Over the past two decades, improvements in process control and developments with plastic powders have resulted in a significant increase in usage.

Rotational Moulding differs from other processing methods in that the heating, melting, casting and cooling stages all occur after the polymer is placed in the mould with no external pressure applied during forming. The rotational moulding process offers tremendous flexibility in both design and production.