Background: Recent Increases in aggressive behavior within psychiatric hospitals have heightened safety concerns. Delayed or ineffective de-escalation may expose staff to patient aggression, leading to serious consequences. Aim: This Quality Improvement (QI) project evaluates the effectiveness of de-escalation training for nurses and mental health workers in managing aggressive patient behavior utilizing the Transtheoretical Model for change in behavior. Method: A pre- and post-intervention design was used with nurse and mental health worker participants. Data collection involved a questionnaire grounded in the Mandt System®, a holistic training program aimed at reducing workplace violence, alongside an inpatient aggression flowsheet tracker. Statistical analysis included descriptive statistics, paired samples t-tests, and Spearman correlations to evaluate changes in patient behavior on the units following the intervention. Result: Forty-five staff members participated in the QI project. Posttest scores showed a statistically significant improvement following the intervention (MD =-0.67333, SD = 0.57422, t (44) = -7.866, p < .001). A positive correlation was observed between aggressive behaviors and Code Grey incidents (r (85) = 0.249, p < .022), with similar trends noted across units (r (85) = 0.229, p < .035). Most staff (90%) reported increased confidence in utilizing de-escalation techniques. Implications: Incorporating violence prevention training into medical and nursing school curricula, as well as staff education. Regular refresher training and up-to-date behavioral management techniques. Conclusion: De-escalation training enhances safety within healthcare settings for both patients and professionals. Keywords: Psychiatric Nursing, Aggressive Behavior, De-escalation, De-escalation Techniques, Adolescent, Forensic, Workplace Violence, and Patient Outcome.