Background: As social media have become pervasive in contemporary society, plastic surgery content has become commonplace. Two of the most engaging and popular platforms are Instagram and Twitter, and much research has been performed with respect to Twitter. Currently, there are no studies comparing and contrasting the two platforms. The aim of this study was to robustly sample plastic surgery posts on Twitter and Instagram to quantitatively and qualitatively evaluate platform content differences. Methods: The hashtag #PlasticSurgery was systematically queried twice per day, for 30 consecutive days, on Twitter and Instagram. Account type, specific media content, possible patient-identifying information, content analysis, and post engagement were assessed. Post volume and engagement between Instagram and Twitter posts were compared. Post characteristics garnering high engagement from each platform were also evaluated. Results: A total of 3867 Twitter posts and 5098 Instagram posts were included in this analysis. Daily total post volume for the 1-month duration of the study was significantly higher on Instagram compared with Twitter. Overall post engagement was significantly higher on Instagram compared with Twitter. Plastic surgeons and plastic surgery clinics represented the majority of accounts posting on both platforms with #PlasticSurgery. Identifiable patient features were much more prevalent on Instagram. The majority of Instagram posts were promotional in nature, outcome-based, or unrelated to plastic surgery. Alternatively, tweets were predominantly educational in nature. Conclusions: For physicians to harness the power of social media in plastic surgery, we need to understand how these media are currently being used and how different platforms compare to one another. This study has highlighted the inherent similarities and differences between these two highly popular platforms.