Teachers' assessment literacy affects the quality of assessments and is, therefore, an essential part of teachers' competence. Recent studies define assessment literacy as a dynamic, contextual and social construct, situated in practice and mediated by teachers' identity and conceptions of assessment. This study provides a further elaboration of assessment literacy by exploring teachers' conceptions of assessment literacy from a sociocultural perspective. Eleven online focus group interviews were conducted within the context of Dutch higher professional education between June and December 2020. A template analysis method was used to analyse the data. Seven interrelated aspects of assessment literacy were identified, namely 'continuously developing assessment literacy', 'conscientious decision making', 'aligning', 'collaborating', 'discussing', 'improving and innovating', and 'coping with tensions'. This representation of assessment literacy, based on teachers' conceptions, may guide teachers' development of assessment literacy in practice.