This paper presents an experimental investigation on the structural performance of an eco-friendly brick masonry slabdeveloped using fly-ash-based brick units and cementitious mortar. The performance is compared with that of a conventional brickmasonry slab having the same geometric configuration and reinforcement arrangement. The study evaluates material strength,water absorption, masonry prism strength, load–deflection behaviour, cracking characteristics and ultimate load capacity. The ecofriendly brick units achieved a compressive strength of 12.8 MPa compared with 10.2 MPa for conventional units, while waterabsorption was reduced from 17.6% to 13.9%. The eco-friendly masonry prism achieved 8.1 MPa compared with 6.8 MPa for thereference masonry. Under flexural loading, the eco-friendly slab attained an ultimate load of 48.9 kN, representing a 14.8% increaseover the conventional slab. The corresponding peak deflection was reduced by approximately 11.2%. The results demonstrate thatthe proposed eco-friendly brick masonry slab provides improved strength and serviceability while offering potential environmentaland economic benefits.Keywords: Eco-friendly brick, fly ash, masonry slab, sustainable construction, flexural strength, load–deflection, masonry prism.