Understanding the correlates of fitness to stand trial is essential to undertaking efficient, evidence-based assessments. We retrospectively analyzed 248 fitness assessment reports pertaining to 115 defendants in Victoria, Australia. Cognitive disorders (e.g., intellectual disability, brain injury) were the strongest predictor of unfitness whereas psychosis was unrelated. Psychiatrists authored the majority of reports (62.4%). Psychologists spent more time assessing the defendant, wrote longer reports, and reviewed more collateral materials. The reports expressly noted that malingering and feigning were considered in only 19% of reports. Fitness evaluations could be improved with standardized interviews, more consideration of statutory definitions of unfitness legal precedent, and embedding feigned unfitness measures into a general assessment procedure.