ABSTRACT: Although various aspects of school leadership during the Covid-19 pandemic have been addressed in the emerging literature, there is a dearth of studies focusing on the effects of the major assessment changes that took place during this period. This article reports on a study of three case-study schools in England, analyzing leaders’ experiences of leading high-stakes assessments. The data suggested that assessment changes during the pandemic impacted several aspects of leadership, especially professional autonomy, moral leadership, the purposes of assessment, managing motivation, and the relationship between assessment and other leadership priorities. None of the leaders wished to retain that approach to assessment, and each argued that these assessment practices had a negative impact on themselves and/or other school leaders they knew. The authors suggest the context of neoliberal and structural reform created a unique political and educational crisis in England. This small-scale study is indicative of the major impact of these revised assessment practices, and the paper suggests that further research is needed to explore the longer-term impact on leaders and their schools.