Whereas many aspects of community health alliances have received attention by researchers and practitioners, leadership has consistently been highlighted as essential to their success. However, much of the writing on alliance leadership remains anecdotal and prescriptive, leaving the fundamental nature and assessment of alliance leadership unexamined. Using qualitative and survey data collected from two large studies of community health alliances, we describe aspects of leadership in alliances, construct a survey-based scale to assess leadership in community health care alliances, and provide initial psychometric assessment and validation of this new measure. Results of the reliability and validity assessments suggest considerable support for the survey-based measure. Although further psychometric testing is needed, the leadership measure holds the potential for researchers to go beyond anecdotal evidence by providing a more objective and comparable basis for assessing the contribution of leadership in health care alliances. © 2011 Wiley Periodicals, Inc.