Research suggests that attachment styles influence the extent to which people utilize social media sites. The present study examined whether attachment styles predict the content of individuals’ Facebook and Twitter posts after being presented with various relationship events. Participants completed personality questionnaires measuring attachment styles, as well as other individual differences already known to affect social media behavior including self-esteem, conscientiousness, and extraversion. Participants were then presented with a positive, negative, or neutral relationship scenario and told to imagine it with their romantic partner in mind. After reading the scenario, participants indicated the likelihood that they would post about this event on Facebook or Twitter and wrote an example post. The posts were scored in regard to how positively or negatively they depicted the relationship and the relationship partner. The results will advance our understanding of how attachment styles predict whether social media sites will be used in relationship-constructive or destructive ways.