There is policy impetus for provision of self-care support (SCS) for children with long-term conditions (LTCs). However, it is not clear what SCS should consist of and how it can be delivered in routine care. This review aimed to synthesise the literature, specifically on SCS of diet and the gut as these components are essential for optimal growth and development and enhanced quality of life. Using an integrative review methodology, studies conducted between January 1990 and July 2020 were systematically identified and methodological quality assessed using the Mixed Methods Appraisal Tool. Twenty-five studies were included. SCS of diet and the gut consisted of support in developing and applying specific knowledge and skills and practical help with incorporating the demands of self-care into everyday life. Key requisites for models of SCS in the context of delivery and uptake in routine care were starting early, keeping it going, being flexible and choosing appropriate outcomes. This review contributes new understanding on the provision of SCS of diet and the gut for school-age children with LTCs, including identification of gaps in the literature and further research needs.