The effects of stable surface oxides on the interface morphologies and strengths of aluminium diffusion bonds are reviewed. Previous approaches, proposed to overcome problems with surface oxides when joining aluminium alloys and composites, are described and compared for both solid-state diffusion bonding and conventional transient liquid-phase diffusion bonding. Non-conventional joining methods, particularly the new method of temperature-gradient transient liquid-phase diffusion bonding and its capability of producing high-strength bonds reliably, also are considered.