The implementation of carbon dioxide capture and storage technology (CCS) is considered an important climate change mitigation strategy, but the viability of this technology will depend on public acceptance of CCS policy decisions. The results of three experiments with students as participants show that whether or not interest groups receive an opportunity to express their opinions in the decision-making process (i.e., group voice) affects acceptance of CCS policy decisions, with inferred trustworthiness of the decision maker mediating this effect. Decision-making procedures providing different interest groups with equal opportunities to voice their opinions instigate more trust in the decision maker and, in turn, lead to greater willingness to accept decisions compared to no-voice procedures (i.e., unilateral decision-making-Study 1) and unequal group-voice procedures (i.e., when one type of interest group receives voice, but another type of interest group does not-Study 2). Study 3 further shows that an individual's own level of knowledge about CCS moderates the desire for an opportunity for members of the general public to voice opinions in the decision-making process, inferred trustworthiness of decision makers, and policy acceptance. These results imply that people care about voice in decision-making even when they are not directly personally involved in the decision-making process. We conclude that people tend to use procedural information when deciding to accept or oppose policy decisions on political complex issues; hence, it is important that policymakers use fair group-voice procedures and that they communicate to the public how they arrive at their decisions.