Women largely dominate the influencer business, and previous studies often either have focused on female social media influencers, or else matched the influencer's gender with the participant's gender in experimental research, as it is assumed that same-gender endorsements may increase persuasion. However, no empirical research is available yet that examines how the influencer's gender affects the persuasiveness of sponsored content posted by this influencer. Therefore, this paper reports on the results from an experimental study (N = 241) testing whether a sponsored post leads to more engagement and greater brand attitude when endorsed by a male vs. a female influencer, and whether the participants' gender moderates this effect. The results revealed no main effects of an influencer's gender, however, an interaction effect was found with participants' gender. More specific, and in line with social identity theory, results suggest that women perceive themselves to be more similar to the female compared to the male influencer, leading to stronger feelings of parasocial interaction, which in turn positively affect brand attitude and post engagement. For men, no differences were found between a male and female influencer on brand attitude nor post engagement through perceived similarity and parasocial interaction. These findings' implications will be discussed further.