<p>Instagram is a popular social media platform that often displays idealized images and messages. Previous research has shown a positive association between Instagram use and body and eating concerns. However, few studies have explored how perceived pressure to conform to appearance standards on Instagram contributes to this relationship. Therefore, this study aimed to: (1) explore the association between Instagram use (time, content, and activities) and perceived appearance pressure on Instagram, appearance-ideal internalization, appearance comparisons, body dissatisfaction, and disordered eating; and (2) evaluate the mediating role of appearance-ideal internalization and appearance comparisons in the relationship between perceived appearance pressure on Instagram and body dissatisfaction, as proposed by the Tripartite Influence Model. Female college students (<i>N</i> = 314, aged 18-30) completed self-report measures and a questionnaire developed to evaluate Instagram use. One-quarter of participants reported spending three or more hours per day on Instagram. Participants reported engaging in editing behavior (55.1%), feeling better about their appearance after receiving many likes (39.8%), and following fitspiration content (53.8%). These factors were associated with some or all of the studied body-image variables. Most participants reported perceived appearance pressure on Instagram. This perceived pressure was, in turn, related to higher levels of appearance-ideal internalization, appearance comparisons, body dissatisfaction, and disordered eating. Additionally, both appearance-ideal internalization and appearance comparisons significantly mediated the relationship between perceived appearance pressure on Instagram and body dissatisfaction. These findings highlight the significant associations between Instagram use and body and eating concerns, raising important implications for research, intervention or educational programs, and policies.</p>