Terrorism researchers have long sought to identify methods for challenging terrorist ideologies. The construction and dissemination of counternarratives has begun to receive substantial attention as a means of doing so. However, the effectiveness of this approach is contingent on message targets’ trust in the counternarrative’s content and source. This article draws from literatures on trust and online source credibility to offer preliminary guidelines for cultivating trust in counternarratives and their sources. By encouraging trust in this manner, practitioners can reduce the likelihood that their counternarratives will be dismissed by their intended audiences—a perpetual challenge to strategic messaging geared toward countering violent extremism.