Portugal was the first country decreeing the mandatory use of the International Classification of Functioning, Disability and Health: Child and Youth (ICF-CY) framework for guiding special education assessment process and to base eligibility decision-making on students' functioning profiles--in contrast with traditional approaches centred on medical diagnosis. Considering the conceptual and pragmatic adjustments underlying this change, this study intends to explore how the professionals involved in assessment procedures perceive the impact of the ICF-CY use. Inscribed in an external evaluation commissioned by the Portuguese Ministry of Education, a content analysis was conducted over 33 focus groups composed of 192 educational professionals selected from a stratified random sampling design. Professionals' opinions revealed that the ICF-CY use supported a better understanding of students' functioning by prompting the description of the environmental influence on students' participation. Challenges were pointed out regarding the ICF-CY use, namely: (1) the need of assessment tools that can provide information about the environmental influences on students' functioning; (2) the establishment of collaboration mechanisms between professionals; and (3) the professionals' ICF-CY training. Based on these three challenges/dimensions, recommendations were drawn in order to prompt a multidimensional approach on educational assessment and intervention planning.