Insulators are materials that don't allow electric current to flow through them easily. They are also known as non-conductors. Insulators are composed of particles which are not loosely attached and are tightly packed together. Their electrons do not move easily so they do not conduct electricity.

Examples of insulators include rubber, plastic, glass, dry wood and certain types of ceramics. Insulators are important in electrical systems as they prevent the flow of electricity in unintended paths, which can result in short circuits and electrical accidents. They also form part of many electrical devices, such as wires and cables.