BackgroundFetal Alcohol Spectrum Disorder (FASD) is a public health problem globally, with South Africa having the highest recorded prevalence of all countries. Government programmes to prevent and manage FASD remain limited because of the lack of a specific policy. Herein, we developed a guideline to inform policy on the prevention and management of FASD in South Africa.MethodsWe applied a modified version of the World Health Organization’s approach to guideline development in three phases. In the first phase, we designed the initial guideline prototype. To do this, we conducted an in-depth interview with policymakers and a focus group with relevant service providers on policy requirements for FASD, a document review of policies on FASD and a scoping review of various interventions for FASD. In phase 2, we refined the initially formulated guideline prototype through a discursive approach with seven local and international experts on FASD. Phase 3 involved refining the prototype using a modified Delphi approach. Forty-three and forty-one experts participated in rounds 1 and 2 of the Delphi approach, respectively. The acceptable consensus for each included policy statement was 85%.ResultsWe identified three aspects of the proposed guideline, which are the approaches and guiding principles, the prevention measures and the management measures. The guideline proposes that a FASD policy should consider lifespan needs, be culturally diverse, collaborative, evidence-based, multi-sectoral and address social determinants of health contributing to FASD. The essential components of FASD prevention policy consist of awareness and education of the dangers of drinking alcohol, access to treatment for alcohol problems and training of service providers. The management components include capacity building related to diagnosis, educating parents regarding the needs and management, appropriate referral pathways, training of teachers regarding classroom management and support for parents and individuals with FASD.ConclusionFASD in South Africa deserves urgent attention. Developing a specific policy to guide programmes could enhance and coordinate the efforts towards preventing and managing FASD. The guideline has the potential to assist policymakers in the development of a comprehensive and multi-sectoral policy for prevention and management of FASD, considering the consensus obtained from the experts.