The effect of an adhesive support on the Mixed-Mode fatigue properties of a metal-to-metal bonded interface was evaluated. Pure Mode I, pure Mode II, and Mixed-Mode fatigue disbond tests were conducted on supported and unsupported bonded samples. The fracture surfaces were observed and related to the fatigue disbond growth rate. The supporting system analyzed was found not to affect the fracture surface under Mode I loading, resulting in similar disbond growth rates for both supported and unsupported bonds. However, under Mixed-Mode and Mode II loading the supporting system improved the fatigue resistance. The improvement was related to different failure mechanisms caused by the supporting system such as Mode II load bearing and a change in the disbond path.