Since the Supreme Court of the United States ruled that individuals with intellectual disability (ID) could not be sentenced to death (Atkins vs. Virginia, 2002), triers-of-fact have been required to make determinations as to whether a defendant or offender meets the required diagnostic criteria. The current study evaluated the impact of crime and juror characteristics on diagnostic determinations. Undergraduate students were assigned to a “low” or “high” heinousness condition, which varied by the crime vignette, and listened to an Atkins hearing. Participants then made a determination regarding the claimant’s disability status (i.e., ID or not ID) and completed several measures assessing personal attitudes and emotions thought to affect legal decision-making. As hypothesized, results revealed that perceptions of crime heinousness and juror characteristics can influence mock jurors’ Atkins decisions. Specifically, the more heinous participants perceived the crime to be, the less likely that they were to conclude the individual had ID.