We review recent experimental research on the behavior of street-level bureaucrats. These front-line government workers are tasked with implementing most government policy in both advanced democracies and developing countries, but their behavior is often difficult to observe. We highlight how experimental approaches have helped to address classic questions about street-level bureaucratic behavior, and then consider design challenges that arise in running experiments in this context. Finally, we raise several ethical concerns about experimentation on street-level bureaucrats, and propose strategies to minimize the social costs, and maximize the social benefits, of such research.