This paper examines the impact of external quality assurance evaluations conducted by the Institutional Evaluation Programmes (IEP). IEP is an international quality assurance agency offering improvement-oriented peer reviews to higher education institutions on a voluntary basis. The paper is based on the results of a survey sent to evaluated institutions, which asked about the extent to which the outcomes of the IEP evaluation had been useful for the institution and about the changes that had been implemented as a result. The findings indicate a good level of impact across a range of areas of institutional activity, although this impact is influenced also by other factors and therefore fully establishing causality is difficult. The study also highlights the links between the impact of IEP evaluations and the context sensitive, improvement-oriented approach used by IEP in its evaluation methodology.