This study explores foundation phase teachers' assessment literacy, and their understanding and use of formative and summative assessment. Using questionnaires, observations and interviews, data were obtained from Grade 1, 2 and 3 teachers from a school each in quintile 2, 3 and 5. Teachers from all three schools demonstrated equally low levels of assessment literacy. While understanding of summative assessment was noticeably higher, all teachers demonstrated very poor understanding of formative assessment. Notwithstanding the small sample size, the study highlights the need for professional development programmes to focus on enhancing teachers' assessment literacy. It also calls for additional research on a conceptualisation of assessment literacy that is relevant to South African teachers, and for determining the impact of concepts and practices advocated in the national assessment and curriculum policies on teachers' use of assessment to address the learning needs of all learners across schools in the different quintile categories.