This report presents results from a program evaluation of the U.S. Department of Energy?s Buildings Technologies Program (BTP) participation in collaborative international technology implementing agreements. The evaluation was conducted by researchers from the Pacific Northwest National Laboratory and the Lawrence Berkeley National Laboratory in the fall of 2007 and winter 2008 and was carried out via interviews with stakeholders in four implementing agreements in which BTP participates, reviews of relevant program reports, websites and other published materials. In addition to these findings, the report includes a variety of supporting materials such that aim to assist BTP managers who currently participate in IEA implementing agreements or who may be considering participation.