The main objective of this study was to investigate the effect of waste glass addition on the properties of fired clay brick. Milled waste glass was added into brick clay at a ratio of 0% (control sample), 2.5, 5 and 10%. Four different series of test samples were produced by extrusion pressing. Samples were fired at 850, 950 and 1050 °C. The microstructures of the fired samples were investigated by scanning electron microscopy. The compressive strength of the fired samples was significantly improved by the addition of waste glass. It was concluded that the amorphous nature of waste glass particles enhanced the sintering action and this led to better strength behaviour.