Although research suggests that feedback on energy usage can generate savings in residential and organizational settings, investigations into the effectiveness of comparative feedback efforts have been fragmented and the findings inconclusive. To help fill this gap, we present research on the effectiveness of a comparative feedback campaign in promoting energy conservation at a university. Surveys were administered in 2009 (n = 2,112) and 2012 (n = 1,601) to measure the extent to which a comparative feedback campaign influenced behavioral determinants, such as conservation-related subjective norms, perceived behavioral control, and attitudes, as well as self-reported behaviors. Results indicate that respondents in participating buildings increased their energy conservation behaviors and perceptions of descriptive norms. Furthermore, participating buildings reduced their energy consumption (kWh/ft²) by 6.5%, whereas non-participating buildings increased energy consumption by 2.4%. Our results show promise for comparative feedback-based campaigns as effective pro-environmental interventions within organizations and provide direction for future research and practice.