This paper describes four case studies in which two types of green walls are implemented for greywater treatment and reuse in Mediterranean countries, Living walls and Green façade. Green walls are vertical vegetated systems that can be integrated into urban environments, providing various benefits. The green walls described in this paper were implemented as part of the NAWAMED project in Mediterranean countries in public facilities with the aim of demonstrating the potential of Nature Based Solutions and reducing the use of potable water by reusing treated greywater. The pilot projects are located in Italy, Jordan, Lebanon and Tunisia, and the treated greywater is mainly reused for irrigation and toilet flushing. In addition, technical indications are provided to foster future implementations of green walls for this specific application and to disseminate sustainable water management schemes.