This review assesses the effectiveness of local opinion leaders in improving professional practice and patient outcomes. Eighteen randomized controlled trials involving over 296 hospitals and 318 primary care physicians (PCPs) were included. The interventions varied, and the outcomes measured included professional performance and patient outcomes. The median adjusted risk difference (RD) for compliance with desired practice was +0.12, indicating a 12% absolute increase in compliance in the intervention group. The effectiveness of opinion leaders varied across different comparisons and studies, with effects ranging from a 15% decrease to a 72% increase in compliance. Opinion leaders alone or in combination with other interventions showed positive effects, but the method of identification and delivery of education did not consistently impact effectiveness. The review highlights the need for further research to optimize the use of opinion leaders in promoting evidence-based practice.This review assesses the effectiveness of local opinion leaders in improving professional practice and patient outcomes. Eighteen randomized controlled trials involving over 296 hospitals and 318 primary care physicians (PCPs) were included. The interventions varied, and the outcomes measured included professional performance and patient outcomes. The median adjusted risk difference (RD) for compliance with desired practice was +0.12, indicating a 12% absolute increase in compliance in the intervention group. The effectiveness of opinion leaders varied across different comparisons and studies, with effects ranging from a 15% decrease to a 72% increase in compliance. Opinion leaders alone or in combination with other interventions showed positive effects, but the method of identification and delivery of education did not consistently impact effectiveness. The review highlights the need for further research to optimize the use of opinion leaders in promoting evidence-based practice.