Insulator may refer to:
- Insulator (electricity), a substance that resists electric current
- Insulator (genetics), an element in the genetic code
- Thermal insulation, a material used to resist the flow of heat
- Building insulation, a material used in building construction to prevent heat loss
- Mott insulator, a type of electrical insulator
- Topological insulator, a material that behaves as an insulator in its interior while permitting the movement of charges on its boundary