Alkali-activated materials (AAM) can be proposed as substitutes for the traditional binders in order to reduce the CO2 emissions for cement and ceramic materials productions. They are based on alkali-activation of precursors able to consolidate at room temperatures. The possibility of using waste-based powders is one of the main advantages of AAM. However, AAM suffer from some drawbacks, mainly their extreme brittleness and their low dimensional stability. One of the main solutions to overcome these problems can be the use of fibres, such as steel, basalt, or polypropylene ones. Moreover, the addition of natural fibres with the scope to obtain a similar improvement could provide a huge environmental benefit. The overall effect of bamboo fibres on the properties of mortars formulated with metakaolin and wastes deriving from the tile industry, activated by alkaline solutions, has been here investigated. The length of the fibres was varied in order to obtain the best properties of the composite materials. A reference mortar without fibres and with the same liquid/binder and binder/sand ratio has been prepared for comparison. All the mortars have been cured at room temperature. The consistency at the fresh state, as well as the microstructural, physical and mechanical properties at the hardened state of the obtained materials have been studied