This study adapts and validates a scale designed to measure Attitudes Toward Mentally Disordered Offenders (ATMDO). It is thought that by monitoring and subsequently improving attitudes, negative potentially damaging milieus within criminal justice, forensic mental health, and society in general can be minimized. Participants (N = 364) were recruited via snowball technique and data collected using an online version of the ATMDO. Psychometric properties were assessed. Test-retest and convergent validity was assessed with additional samples A (N = 30) and B (N = 50) respectively. Utilizing a cross-sectional design, differences in ATMDO scores across occupational groups were compared. The ATMDO demonstrates robust internal structure, reliability, and validity. Although ATMDO scores did not differ significantly across occupational groups, some differences were seen at a factorial level. Regression analysis demonstrates the influence of both demographic and occupation-related variables in predicting ATMDO scores. The ATMDO is robust and has clinical utility for comparison of professional groups or institutions, and within recruitment procedures. A model is proposed for the effects of exposure (catalyst factor) and professional certification training (moderating factor).