Fetal alcohol spectrum disorder (FASD) is a prevalent neurodevelopmental condition. Despite FASD being recognized as a clinical disorder there is no globally agreed set of diagnostic criteria. Accurate and timely diagnosis of FASD is imperative to inform clinical care, optimize outcomes for individuals accessing assessments and their families, as well as for research and prevention strategies. To inform movement towards a unified approach, the present study aimed to capture an international perspective on current FASD diagnostic criteria, as well as potential barriers and facilitators to unification. An online survey was created using REDCap and sent to clinics identified and contacted via internet searches. Quantitative data were presented using descriptive statistics and open-ended questions analysed using content analysis. The survey captured information about each clinic’s current diagnostic approach, whether they would support a unified method, and the barriers and facilitators for a consistent international FASD diagnostic approach. Fifty-five (37.4%) of 147 FASD clinics identified worldwide participated. The majority (n = 50, 90.9%) of respondents supported a unified approach. Content analysis identified a lack of collaboration as a key barrier, while strong leadership in guideline creation and implementation emerged as a central facilitator. These barriers and facilitators can be used to guide future collaborative efforts towards implementing consistent diagnostic criteria.