We investigate how directors’ positions within board interlocking networks influence their monitoring behaviors from a social network perspective. We argue that the effectiveness of directors’ monitoring of a firm's management depends on their ability to overcome the information barrier and their motivation to develop a public reputation in the directorship market. We further contend that network centrality can supplement directors’ existing information set and facilitate reputation spillover, leading to an increase in the extent of their dissent on boards. We analyze the unique individual-director-level data of Chinese firms and find that directors occupying positions of greater centrality in the board interlock network are more likely to dissent. We then examine the underlying mechanisms of information and reputation through two moderators: firm transparency and media mention of a director. We also find that the effect of network centrality on dissent is weaker for independent directors. Our study advances the corporate governance literature by examining the micro-foundations of board monitoring and providing a social network perspective.