Energy performance gap refers to the discrepancy between the predicted and the realized energy savings after buildings adopt energy-efficient technologies. This study identifies and analyzes the organizational, behavioral and engineering factors related to the energy performance gap. 117 completed surveys from facility managers in the United States were obtained in 2017. We find that the primary reasons for the energy performance gap are (1) occupants using more energy than designed, (2) more occupants than originally designed, and (3) energy efficient technology failures. An analysis is conducted using probit models. The results show that LEED and Energy Star buildings are more likely to have tenant lease agreements to eliminate asymmetric information for new tenants. Energy Star buildings are more likely to have sub-metering for air conditioning. However, LEED buildings are associated with factors causing the energy performance gap, such as lack of sub-metering for AC and longer operating hours. Building characteristics such as occupancy rate, building type, ownership and building location influence the impacts of the identified socio-technical factors. Finally, several suggestions to mitigate the energy performance gap are proposed, such as incentives to facility managers, commissioning, energy performance contracting, and occupants' behavioral change.