A better understanding of firms' response strategies to regulatory uncertainty enables policymakers to improve policymaking efficiency and to enhance the effectiveness of regulation. Based on a literature review, we categorize responses according to their objective toward regulatory uncertainty into four strategies: avoidance, reduction, adaptation, and disregard strategies. Unique data from a worldwide cross-industry survey show that firms predominantly pursue reduction, and to a lesser extent adaptation and disregard strategies, in response to post-Kyoto regulatory uncertainty. Surprisingly, firms in fact only sporadically pursue avoidance strategies, in contradiction to their own public announcements commonly made during policymaking to realize such strategies. The degree of regulatory uncertainty perceived and its interpretation as a threat increase the pursuit of most of these strategies. In addition, firms' response strategies to post-Kyoto regulatory uncertainty differ across industries and partly across regions.