The opioid crisis in Ontario has led to a surge in preventable overdose deaths. Challenges in the mental health and addiction system, along with various contributing factors, have amplified this crisis. Underutilization of data exacerbates service gaps and hinders innovative solutions. Through stakeholder engagement, interrelated problems emerged, emphasizing the pervasive data underutilization. This research explores data usage in mental health and addictions, focusing on the opioid epidemic in Ontario and comparative jurisdictions. To improve service quality, Ontario should implement a comprehensive data management strategy. Two key recommendations include increased investment in exploring additional data use cases and evaluating policy initiatives using dynamic models throughout a patient’s journey.