Language assessment literacy (LAL) has recently gained substantial attention among language educators and other stakeholders. However, existing models focus almost exclusively on teachers, test developers, and administrators, and lack students' perspectives in their conceptualizations. To address this gap, with this exploratory study we aimed to understand young learners' LAL. The participants were fourth- and sixth-grade students (ages 9-10 and 11-12, respectively, with 10 participants in each age group) in China. After taking English mock tests, the children participated in individual, semi-structured interviews that covered their understanding of the following: (a) assessment purposes and theories (their knowledge about how assessment works); (b) assessment skills (their views of assessment designs, procedures, and content); and (c) assessment principles (their notion of fairness, cheating, and feedback). The data were analyzed qualitatively in line with current LAL models. The results suggest that the children already had substantial assessment literacy in knowledge, skills, and principles. Although their teachers' assessment practice remains form-focused, children generally want more communicative-based and diagnostic assessment. They also want more cognitively challenging and enjoyable assessment tasks. Our findings provide solid supporting evidence for the importance of considering students' perspectives, along with the views of other stakeholders, in order to have a more balanced understanding of LAL.