This research examined how adolescents' internalizing symptoms, such as depression, anxiety, and loneliness, relate to the content of their Facebook communication and the responses they receive from peers on Facebook. Participants ( = 125, 56 female, age 18) reported on their internalizing symptoms in the summer following 12 grade, and downloaded an application to their Facebook account that stored the content of all of their Facebook communication to secure, online archive. Two months of participants' status updates and comments and peers' comments were coded for content. Relations between internalizing symptoms and Facebook communication differed for girls and boys. For girls, internalizing symptoms predicted several types of Facebook content: negative affect, somatic complaints and eliciting support. In contrast, internalizing symptoms were not related to boys' Facebook posts. Relations between internalizing symptoms and peers' responses on Facebook also differed by gender. For girls, internalizing symptoms positively predicted receiving more peer comments expressing negative affect, and peer responses offering support. For boys, internalizing symptoms did not predict any of the measured peer responses. These findings suggest that girls prone to internalizing symptoms use Facebook in ways that appear similar to co-rumination, by expressing problems to friends and receive possibly reinforcing feedback in return.