This guidance document is intended to increase the awareness and understanding of optimal maternal nutrition practices and to support people who are working to translate optimal practices into feasible actions and programs for a given country or region. This guidance presents the different elements of creating and implementing formative research for maternal nutrition, including: (1) understanding the general maternal nutrition context by using all readily available data and information, (2) choosing the best research methods and participants, and (3) developing effective research guides and tools.