The literature on unintended consequences of economic sanctions is well developed, but few studies have addressed terrorism in target states, and none have assessed whether that terrorism becomes more effective when sanctions are in place. In this study, we test whether economic sanctions lead to an increase in the lethality of terrorism. Using data from multiple sources, we find that while sanctions are unrelated to the rate of success of terrorist attacks, they are positively associated with the number of fatalities resulting from terrorist attacks. These findings further the need for policymakers to consider the consequences sanctions have on the target country populace.