This entry elucidates the opinion leader construct, distinguishing it from positional leadership and from elites. The attributes of high connection in a social network, high persuasiveness, and mavenness characterize the opinion leader. In contrast to the notion of a generalized opinion leader, the argument advocates the position of a fuzzy domain‐specific knowledge (mavenness) conception of the opinion leader. Subsequent discussion focuses on methods of identifying opinion leaders, including both self‐report and observational methods. A treatment of the effects of opinion leadership, distinguishing effects on beliefs, attitudes, and behavior, ensues, followed by acknowledgement of opposing viewpoints. The entry also acknowledges limitations of the associated two‐step flow model, that is, in some cases only one step may occur, whereas in other cases multiple steps may emerge. It then concludes with recommendations for advancing opinion leadership scholarship, including a sketch of the types of experiments and subsequent cumulation of evidence required to draw firm conclusions as to the usefulness of the concept of the opinion leader.