This presentation offers six conditions that position an evaluator to use evaluation evidence to effectively speak truth to power. These are illustrated drawing on a summative evaluation of the Ford Foundation’s $54m Strengthening Human Rights Worldwide global initiative, and a developmental evaluation of the Atlantic Philanthropies’ Tekano Atlantic Fellows for Health Equity leadership development programme. The factors are: 1) timing of the evaluation; 2) willingness of both evaluation commissioner and evaluand to learn and improve; 3) the evaluator’s capacity for and practice of relationship trust-building; 4) the production of high quality evidence; 5) commitment to and comfortableness with the role of evaluator as advocate, as long as this does not undermine the ability of those involved to speak for themselves; and 6) terms of reference that allow and fund the evaluator to independently communicate findings in ways most likely to influence the practice of the evaluation commissioner and broader constituencies.