A child's early school years provide a crucial platform for them to develop fundamental movement skills (FMS), yet it has been acknowledged that there is a shortage of suitable FMS assessment tools for teachers to use within schools. To begin to address this shortfall, the purpose of this study was to elicit expert recommendations for the design of a FMS assessment tool for use by primary school teachers. A multi-phase research design was used, involving two scenario-guided focus groups with movement experts (n = 8; five academics and three practitioners). Data captured in both focus groups were transcribed verbatim and thematically analysed. Three dichotomous dilemmas emerged from the data in relation to assessing children's movement competence: (a) "Why?" For research purposes or to enhance teaching and learning?; (b) "How?" Should the assessment setting be engineered or natural?; and (c) "What?" Should the detail of the assessment be complex or simple and should the nature of the tasks be static or dynamic? These findings suggest that any future development of movement competence assessment protocols for use by primary school teachers needs to consider the specific purpose and context of the assessment.