Employing nurses as opinion leaders to implement guidelines may be a promising implementation activity. Until now, insight into necessary competencies of nurse opinion leaders is lacking. We studied and supported aspiring nurse opinion leaders, using a training program based on social influence and implementation theory. Twenty-one competencies were identified, of which the most important were cooperating, communicating, delegating, giving feedback, networking, and information processing. Understanding and addressing these competencies may support the implementation of evidence-based guidelines.