Cultural fit is a concept that can be applied to the effectiveness of one's evaluation practice as well as the interventions that seek to help people. We argue that there is substantial vagueness about being culturally competent, or culturally responsive, or both, and that the concepts these terms are attempting to embody can be viewed better as a continuum of skills, knowledge, attitudes, and positioning. We propose replacing these terms with the concept of cultural fit; that is, the contextual stance or positioning of a practitioner or evaluator as an insider, of the same culture(s) as the service user or evaluand, and having a congruency with the service user or evaluand's core cultural values. We argue that the cultural fit between organisational staff and service user creates grounds for greater effectiveness, and therefore the concept of cultural fit is potentially an important effectiveness criterion for interventions and evaluators. Cultural fit also has relevance both for commissioners of evaluation (in reflecting on how they might reasonably assess the cultural fit of an evaluation team, or evaluator, or both), and for evaluators themselves, as a way of measuring their own cultural fit and how this impacts on their effectiveness as an evaluator.