This scoping review provides an overview of the tools used to assess for early childhood caries (ECC) in Nigeria. A search of the literature in African Journals Online, Google Scholar, Medline, and Cochrane database was conducted in June 2023 using the PRISMA-ScR guidelines. A combination of keywords related to caries risk assessment, preschool children, and evaluation tools was used for the search. Studies reported in English and assessing ECC were extracted. Descriptive statistics were used to summarise the information on study characteristics, types of caries assessment tools, and study outcome. Caries assessment tools were divided into behavioural, social, and biological. After screening 964 potential studies, 16 were included in the review. ECC assessment tools were categorised into behavioural (snacking, frequency of consumption of refined carbohydrate in-between-meals, dental service utilisation, frequency of tooth brushing, use of fluoridated toothpaste, breast and bottle feeding patterns and duration), biological (birth rank, age, sex, anthropometric measures, molecular characterisation of isolated organisms, presence of plaque), and social (socioeconomic status of the child’s household, mother’s level of education, maternal income, occupation of the father, maternal decision-making ability). Twelve studies used behavioural assessment tools, 11 used biological, and 11 used social tools. Furthermore, 11 (70.1%) used a combination of tools, four (25.0%) used only biological tools, and one (6.2%) used only behavioural tools to assess ECC experience. No study screened for the risk of caries. In conclusion, we identified the need for comprehensive studies to identify the risk indicators of ECC in Nigeria. This will support the development of a caries risk assessment tool appropriate for the country context.