Fire burnt clay bricks are a common building material used in engineering practice in Uganda. This study aims at investigating the use of rice husk ash as a stabilizer in fire burnt clay bricks. The methods used to attain the objectives include soil tests such as the Sieve analysis and Atterberg limit tests on the soil to be used in the bricks to determine its physical properties, X-Ray Fluorescence spectroscopy on the Rice husk ash to determine the chemical composition and tests mainly focusing on the compressive strength and water absorption parameters of the stabilized earth blocks. Some key parameters in the study include the temperature variations of the materials being used and the effect on the final mechanical properties of the brick. This research identifies that the optimal ratio of RHA to soil is 9:1 with the RHA being heated at 7000C for 6 hours explaining the influence of the chemical composition of the ash on the clay minerals used when brick making. With this mix, an increase in compressive strength of up to 143.5% was deduced after stabilisation with RHA.