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 paper 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. We 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.