How can we encourage the adoption of new digital financial services? We use an RCT with 115 microfinance groups in Ghana to understand the respective roles of individual incentives to adopt a new technology and endorsement of the technology from a trusted peer. We study this in the context of mobile banking services, a technology allowing transfers between a mobile phone and bank account, dramatically lowering the costs of accessing the bank account. We find that while individual incentives increase adoption of mobile banking services by 50%, adding endorsement by a peer doubles the impact of the individual subsidy alone. Peer endorsement is particularly effective at increasing confidence in dealing with fraud and peer interaction around mobile banking. The increased use of mobile banking services leads to 30% higher savings in the linked bank account 6 months later. Our study highlights the importance of peers in encouraging technology adoption and facilitating formal financial inclusion.