Mannar may refer to:
- Mannar, Alappuzha, a town in Alappuzha district, Kerala, India
- Mannar, Kaduthuruthy,a town in Kottayam district, Kerala, India
- Mannar, Sri Lanka, a town in northern Sri Lanka
- Mannar District, a district in Sri Lanka
- Mannar Electoral District, a former electoral district in Sri Lanka
- Mannar Island, an island in Sri Lanka
- Gulf of Mannar
- Mannargudi, a town in Tamil Nadu, India