The Idaho legislature passed their right-to-work law in 1986. Idaho provides an interesting case study for the effects of the law because it adopted the law during a period in which unionization had already declined substantially in the United States. This article provides evidence on the industrial organization consequences of right-to-work laws by jointly examining the trends in Idaho’s unionization rate and industrial performance before and after 1986, using neighboring states as controls. The authors find that unionization declined substantially starting a few years before the passage of the law, and this decline persisted thereafter. Furthermore, the post-law growth rates in manufacturing employment and the number of establishments far exceeded their pre-law counterparts. As a result, Idaho gradually became more like an “average” right-to-work law state in terms of its unionization rate and the employment share of manufacturing, diverging from the patterns exhibited by states without a right-to-work law.