Description:Many variations of injection moulding have been developed and one of the rapidly expanding fields is multi-material injection moulding. This review looks at the many techniques being used, from the terminology to case studies. The three primary types of multi-material injection moulding examined are multi-component, multi-shot and over-moulding. The basic types of multi-material injection moulding, the issues surrounding combining different types of polymers and examples of practical uses of this technology are described.