Corner castings or corner fittings are the corners of an ISO container. They are structural elements that allow containers to connect to: other containers, both horizontally and vertically, and modes of transport including ships, rail and road. Additionally, corner castings allow containers to be picked up and moved as needed.

All 8 corner castings of a 96" wide ISO container or corresponding CTU must be particularly strong. They work together with the corner posts and other basic components of the container frame to absorb the forces exerted by locking units or lashings when the container is stacked, superimposed on each other, during handling and during shipping.