Background: UNESCO [(2015). Quality Physical Education Guidelines for Policymakers. Paris: UNESCO Press.] highlighted the importance of developing physical literacy (PL) from childhood, although it remains unclear how best to evidence an individual's PL journey. The aim of this study was to explore key stakeholders' views of current practice, future directions and effective implementation of PL assessment, with a view to informing the development of a rigorous, authentic, and feasible PL assessment. Methods: Purposive samples of children aged between 6-7 years (n = 39), 10-11 years (n = 57), primary school teachers (n = 23), and self-defined experts with an interest in PL (academics n = 13, practitioners n = 8) were recruited to take part in a series of concurrent semi-structured focus groups. Each group included a maximum of six participants, lasted on average 40 (30-90) minutes were audio-recorded and transcribed verbatim. Data were analysed using deductive and inductive thematic analysis and key themes were represented by pen profiles. Results: Higher order themes of (i) existing assessments, (ii) demand for PL assessment, (iii) acceptability of PL assessment, and (iv) factors related to implementation of PL assessments were identified. All stakeholders viewed the assessment of PL as important, but in line with well-established barriers within physical education (PE), assessment was not a priority in many schools, resulting in a variability in existing practice. No assessment of the affective and cognitive domains of PL was reported to be in use at participating schools. All stakeholder groups recognised the potential benefits of using technology within the assessment process. Children recognised that teachers were constantly making judgements to help them improve, and agreed that assessment could help record this, and that assessment should be differentiated for each child. Teachers widely reported that future assessment should be time-efficient, simple, and useful. Conclusion: Study findings revealed a demonstrable need for a feasible PL assessment that could be effectively used in schools. To our knowledge, this is the first attempt to involve these stakeholders, and triangulate data, to inform future PL assessment and practice. Findings provide an evidence base to inform the onward development of a conceptually aligned PL assessment tool, suitable for use in schools. In turn, this will enable robust, empirical evidence to be collated, to evidence theory, and inform practice and policy.