While research has shown mixed effects of social media on mental health and well-being, little is known about the association between social media attitudes and objective measures of social interaction, such as linguistic authenticity. This study examined the relationship between self-reported social anxiety, linguistic authenticity, and Instagram contingent self-worth (ICSW). A total of 149 adults with active Instagram accounts completed online questionnaires and shared their Instagram comment data. Automated linguistic analysis of authenticity was performed on participants’ comment data using validated algorithms. Multiple linear regression showed that ICSW significantly moderated the relationship between social anxiety and linguistic authenticity, whereby higher levels of social anxiety marginally predicted lower linguistic authenticity at high levels of ICSW. As social media use continues to rise, this study emphasizes the need to explore the impact of social media interactions on emotional and social well-being.