An experiment tested whether user-generated pro-environmental messages (UGC) enhanced environmental self-identity among message creators. Participants were randomly assigned to create a message about saving energy, view a message with similar content ostensibly created by similar others, or view irrelevant messages. Those who created their own messages had greater post-message self-identity than those in the other two conditions. Additionally, those who created their own messages had greater post-message intentions to save energy in the near future than those in the other two conditions, and behavioral intentions were positively correlated with self-identity. Implications for campaigns and educational efforts are discussed.