This study aims at investigating the performance of eco-sustainable lightweight bricks reinforced with natural fibres (NP) in the context of environmental and structural issues in construction in Tanzania. A total of 342 samples were tested using an experimental design for compressive strength, density, water absorption and thermal performance (TP). The statistical analysis showed that the eco-sustainable bricks have a significant effect on the environmental sustainability (ES) and acceptable mechanical properties. The overall performance of bricks and thermal insulation properties were found to be significantly improved with NPs. All hypotheses were supported from reliability and regression (p<0.001) that accounted for 50.4% of the variance. The results show that the local resources can be used to produce affordable and sustainable houses. The study offers guidelines for policymakers and engineers in developing countries that promote environmentally friendly construction technologies.