Despite the increased importance of school inspection in recent years, the current knowledge base does not provide a clear view on the effects and side effects of being inspected. More evidence is needed in more diverse educational contexts. This article responds to this need with a quantitative study on the effects and side effects of school inspections on Flemish schools. In total 2624 respondents from 130 primary and secondary schools participated in the study. The article discusses the conceptual, instrumental, symbolic and strategic effects of inspection and its impact on self-efficacy and collective efficacy. Regarding side effects, the emotional impact is discussed alongside disturbing effects, misleading activities by schools and individual teachers and the impact on staff members’ personal lives. Furthermore the article distinguishes between the responses of staff members from schools with a positive inspection judgement and those with a less favourable judgement, and between the responses of teachers and of members of the school management teams. This study is embedded in the Flemish educational context. The results of our study are put in perspective next to results of studies in other educational contexts. Several particularities of the Flemish educational context (and how they may have affected our results) are discussed.