Guaira may refer to:
- Guaíra Falls, former waterfalls on the Paraná River along the border between Brazil and Paraguay
- Brazil
- Guaíra, Paraná
- Guaíra, São Paulo
- Paraguay
- Guairá Department
- Salto del Guairá, Canindeyú Department
- Venezuela
- La Guaira, the capital city of the Venezuelan state of Vargas and the country's chief port