Digital systems are increasingly becoming central to the running of contemporary schools. A range of digital tools are also adopted by teachers to facilitate face to face teaching and learning and more recently to accommodate remote schooling. Similarly, digital technologies lie at the heart of how students support their learning but also interact with peers. These digital practices raise questions in relation to teachers' own critical digital literacies as well as their role in developing students' critical digital literacies. This paper presents the findings of a qualitative study that aimed to develop an understanding of teachers' current experiences and future needs relating to critical digital literacies within school contexts. Drawing on empirical data collected during focus group interviews with primary and secondary school teachers in Finland, Italy, Spain and the UK this paper looks at teachers' perceptions of critical digital literacies and explores whether and how these are manifested in their practices. Findings revealed that different dimensions of critical digital literacies were more prevalent for each national group and highlighted the disjuncture between how Critical digital literacies (CDL) is defined and perceived in academic research with a stronger emphasis on the "critical" and between the more "twenty-first century skills" oriented policy agendas and curricula which inform teachers' practice. The paper goes on to discuss the implications of these findings and identifies gaps in relation to teachers' understandings of critical digital literacies. Last, it offers original insights for future policymaking, research and practice regarding the challenges of supporting teachers with developing critical digital literacies.