In this study, we examine the relationships between principals' evidence-oriented attitudes and their data use in school leadership practices. Based on theoretical assumptions and existing empirical research, we develop hypotheses on the correlation of evidence-oriented attitudes, epistemological beliefs and principals' data use. We test these hypotheses based on data collected from a sample of N = 297 principals at 153 schools of different types using structural equation modelling. The findings show that the examined attitudes and epistemological beliefs have a slight, yet significant influence on principals' data use. In particular, principals' skepticism towards knowledge or academia influences data use. We conclude by addressing the limitations of our study and the challenges they pose for future research as well as implications for evidence-based school improvement.