This paper reviews evidence on agent networks of microfinance institutions and other financial services providers, which have expanded rapidly in recent years in some low- and middle-income contexts. There is emerging evidence that clients become more financially active as a result of the convenience and security of transacting with agents, especially with respect to depositing, withdrawing, and transferring funds. Agent networks could also help increase the savings of low-income clients, although evidence suggests that commitment devices may also be required, and there is little evidence that agents expand credit to clients, although they can facilitate loan repayment. Building on their physical and social proximity to customers, agents can become a potential gateway for expanding and deepening financial inclusion, but the pricing of agent transactions and consumer protection remain important considerations.