Existing conceptualizations and measures of transformational and transactional leadership have unclear theoretical bases, confound leadership and its effects, and are not necessarily suitable for public organizations. Overcoming these problems is necessary to test how leadership affects performance. Many public administration scholars apply the concepts, emphasizing the need to ensure that the concepts are applicable in both public and private organizations. The article reconceptualizes transformational and transactional leadership and develops and tests revised measures that can be employed on employees and leaders, are robust in terms of repeated use by the same respondents, and are applicable to public and private organizations alike.