Young women increasingly spend time on social media, but the relationship of this exposure to body image is still in the initial stages of exploration. In this study the authors used social comparison theory to examine the relationship between time spent on Facebook and body image. A survey of 881 U.S. college women was conducted in April-May 2013. Findings showed that 10.1% had posted about weight, body image, exercise, or dieting, and 27.4% had commented on friends' posts or photos. More time on Facebook related to more frequent body and weight comparisons, more attention to the physical appearance of others, and more negative feelings about their bodies for all women. For women who wanted to lose weight, more time on Facebook also related to more disordered eating symptoms.