A cast net, also called a throw net, is a net used for fishing. It is a circular net with small weights distributed around its edge.

The net is cast or thrown by hand in such a manner that it spreads out on the water and sinks. This technique is called net casting or net throwing. Fish are caught as the net is hauled back in. This simple device is particularly effective for catching small bait or forage fish, and has been in use, with various modifications, for thousands of years. On the US Gulf Coast, it is used especially to catch mullet, which will not bite a baited hook.