ACM MobiCom 2014, the Annual International Conference on Mobile Computing and Networking, is the twentieth in a series of annual conferences sponsored by ACM SIGMOBILE dedicated to addressing the challenges in the areas of mobile computing and wireless and mobile networking. The MobiCom conference series serves as a highly selective, premier international forum addressing networks, systems, algorithms, and applications that support mobile computers and wireless networks. In addition to the regular conference program, MobiCom 2014 will include a set of workshops, panels, research demonstrations, and a poster session that includes the ACM Student Research Competition. This year, MobiCom will be featuring the mobile app competition succesfully introduced last year. The conference will be held in Maui, Hawaii.