This paper reviews how strategic impact assessments (SIAs) may be used to strengthen the appraisal and evaluation of policies, plans and programmes (PPPs) for enterprise development (ED) in developing countries. Since this is a relatively new area for the application of SIA, it is developmental in character. It draws upon the wider literature on different forms of impact assessment, including strategic and project levels of assessment; and economic, social and environmental forms of assessment. It also takes account of the main types of enterprise development strategy that may require assessment - financial services; business development; improving the regulatory environment, and improving the infrastructure environment - and the institutional context in which this may take place. The paper is divided into six sections, which, after an Introduction, cover: