This study assessed the role of expert testimony and just world beliefs (JWB) in decisions made in a sexually violent predator (SVP) trial. Three participant samples (student, juror, and community; total N = 534) completed items measuring JWB and watched a 1-hour videotaped trial simulation that featured a psychologist offering different types of expert testimony in a SVP hearing. After the opening statements and at the end of the trial presentation, participants made commitment decisions and rated their confidence in their decision. They also rated the expert testimony on influence, credibility, scientificness, and confidence. Results indicated that favorable attitudes toward the expert mediated the relationship between JWB and commitment decisions. This relationship did not differ depending on type of expert testimony (clinical vs. actuarial) proffered. The legal and policy implications of the findings are discussed.