This paper presents a theoretical model and empirical evidence to explain the occurrence of tax amnesties. We treat amnesties as endogenous, resulting from a strategic game between many taxpayers discounting future payments from punishment and a government that balances costs and benefits of amnesty programs. From the model we derive hypotheses about the factors that should influence the occurrence of tax amnesties. To test these predictions empirically, we rely on amnesty information from US States between 1981 and 2011. In line with the theoretical model, our empirical findings suggest that the likelihood of amnesties is mainly driven by a government's fiscal requirements and the taxpayers' expectations on future amnesties.