Purpose - The purpose of this paper is to contribute to studies of family decision making during food buying. In particular a theoretical framework is proposed for structuring future studies of family decision making that include children's influence and participation at specific stages of the process. Design/methodology/approach - The conceptual framework is developed on the basis of earlier theoretical work focused on family shopping as well as an ethnographic study of parents and children. The framework was refined after testing in a survey with 451 Danish families with children aged ten to 13 using questionnaires for both children and parents. Findings - Family food decision making is often a joint activity, and children's active participation, among other things, determines the influence they gain. Parents and children do not always agree on how much influence children have in the various stages of the process, indicating the importance of listening to both parties in research into the family dynamics and processes involved in everyday food buying. Research limitations/implications - Future research should further extend the knowledge about the areas where children have influence, about the techniques used by children to achieve influence, and more about those factors that explain when they gain influence. Practical implications - Marketers can benefit from the findings when promoting food products to adults as well as to children. Specifically, the findings suggest that children have most influence on decisions regarding easily prepared meals. Originality/value - This mixed-method approach provides interesting new results, and the main findings emphasise the importance of looking at food decision making as a joint activity where children participate actively and gain influence.