Social media is an increasingly important yet understudied context for eating behaviors in general and veganism in particular. In four studies, we first explored and described the information environment the platform Instagram presents related to veganism. Second, we examined how engaging with this environment is associated with offline eating intentions via psychological mechanisms. We scraped datasets of Instagram posts tagged with #vegan (44,316 posts in total) and employed network analysis with their hashtags (Study 1), as well as clustering with images and sentiment analysis with texts (Study 2). Studies 3 (N = 117) and 4 (N = 251) used online surveys to investigate associations between different forms of engaging with social media content, psychological constructs, and offline eating intentions. Posts about veganism were frequently related to food, health and fitness, cosmetics, and photography. Images most often depicted food (34.7%), non-food products (30.4%), people (7.9%), and animals (2.0%). The sentiment of most posts was positive. Being exposed to Instagram content about veganism was more strongly and consistently associated with eating intentions than active forms of engagement. Attitude and self-identity emerged as the most relevant mechanisms for these effects. Food is the most prominent yet not sole topic among posts about veganism on Instagram, and hashtags used in this context partially relate to motives for following a vegan diet. Exposure to this information environment might influence offline eating decisions via psychological mechanisms. With growing usage and its potential influence, social media should receive increasing attention in (health) psychological research and practice.