Objective: Drug-induced QT prolongation is a critical adverse effect associated with life-threatening ar rhythmias. This study evaluated the impact of clinical pharmacist-led interventions on physicians’ knowledge, attitudes, and practices (KAP) regarding QT prolongation management. Material and Method: A quasi-experimental study was conducted at three Iraqi hospitals (January–April 2025) involving 53 physicians and 100 patients. Pre- and post-intervention assessments were performed using validated questionnaires. The intervention included educational lectures, checklists, and pharmacist consultations targeting QT-prolonging drug risks, ECG monitoring, and electrolyte management. Result and Discussion: Post-intervention, physicians demonstrated significant improvements in knowledge (mean score: 4.3±1.4 to 5.6±1.7, p<0.001), with 26.4% achieving "good knowledge" (vs. 5.7% pre-intervention). Attitudes improved markedly, with 60.4% rating pharmacist collaboration as "important" (vs. 35.8%, p=0.0046). Clinical practices showed the most pronounced change: frequent prescribing of QT-prolonging drugs dropped from 18.9% to 0% (p=0.0067), and ECG monitoring adherence increased. The prevalence of QT prolongation in patients decreased non-significantly from 36% to 29% (p=0.29). These findings align with global evidence supporting pharmacist-led interventions in cardiovascular risk mitigation. The study highlights the value of interprofessional collaboration in enhancing medication safety.