The principle difficulty when joining magnesium (Mg)-aluminium (Al) lies in the existence of formation of oxide films and brittle intermetallic in the bond region. However, diffusion bonding can be used to join these alloys without much difficulty. Temperature, pressure, and holding time are the three main variables which govern the integrity of a diffusion bond. This paper focuses on the effect of these parameters on diffusion layer thickness, hardness and strength of AZ31B magnesium-AA2024 aluminium dissimilar joints. The experiments were conducted based on three factors, five-level, and central composite rotatable design with full replications technique. Empirical relationships were developed to predict diffusion layer thickness, hardness and strength using response surface methodology. From this investigation, it is found that bonding temperature has predominant effect on bond characteristics.