Elected representatives in many countries are legally allowed to carry out (un)paid jobs in addition to their political mandate, often referred to as 'moonlighting'. Despite the important selection and incentive effects such outside positions might engender, academic studies evaluating the prevalence, desirability and/or consequences of politicians' moonlighting have remained relatively scarce; often due to severe data restrictions. In recent years, however, more stringent disclosure rules have increased data availability, and large-sample analyses are becoming increasingly feasible. Besides surveying recent empirical contributions to this developing research field, this paper also outlines unresolved issues and thereby develops an agenda for future enquiry.