The present work examined the influence on thermal properties of the incorporation of banana pseudo-trunkfibres in a cementitious matrix mortar that can be used as rendering or masonry block. The banana pseudo-trunkfibres are extracted, cut and characterized. Then the mortars are made with different proportions of fibres and characterized in order to identify the parameters influencing the characteristics of the material, both in the fresh and hardened state. The physical, mechanical and thermal tests carried out have shown an increase in the porosity and water absorption of the mortar with a decrease in the density, thus making the mortar lighter. It was also noted a decrease in the mortar's flexural and compressive strengths as a function of the percentage of fibres; nevertheless, the values remain within an acceptable range.