Access to and use of mobile telephony in sub-Saharan Africa has increased dramatically over the past decade. Mobile telephony has brought new possibilities to the continent. Across urban-rural and rich-poor divides, mobile phones connect individuals to individuals, information, markets, and services. These effects can be particularly dramatic in rural Africa, where in many places mobile phones have represented the first modern telecommunications infrastructure of any kind. Mobile phones have greatly reduced communication costs, thereby allowing individuals and firms to send and to obtain information quickly and cheaply on a variety of economic, social, and political topics. An emerging body of research shows that the reduction in communication costs associated with mobile phones has tangible economic benefits, improving agricultural and labor market efficiency and producer and consumer welfare in specific circumstances and countries. This paper first examines the evolution of mobile phone coverage and adoption in sub-Saharan Africa over the past decade. We then explore the main channels through which mobile phones can effect economic outcomes and appraise current evidence of its potential to improve economic development. We conclude with directions for future research and outline the necessary conditions for mobile phones to promote broader economic development in Africa.