Background: The internalisation of gender stereotypes has long-term impacts on the aspirations, opportunities and psychosocial well-being of people. The main objective of this study is to measure the adherence to gender roles among children, analysing the link between their roles’ internalisation, the family context and the socioeconomic environment. Method: During the Spring 2021, a survey was carried in Rome on children aged 8–11 through a structured questionnaire. The explanatory dimensions of the analysed topics were identified and a survey questionnaire with an ad hoc administration method were developed. Results: The results show a widespread internalisation of traditional gender roles among the respondents and differences by sex were found, since their acceptance is higher among boys for male roles and among girls for female roles. As the age increases, the adherence to male roles decreases for both boys and girls, while high levels of prosociality resulted in a lower adherence to female roles among boys. No significant relations were found with family and environmental variables. Conclusions: These findings show how the internalisation of gender stereotypes is already traceable at this age, and due to a different path of primary socialisation, boys and girls develop their gender identity consistent with social expectations. The lack of significant relations with environmental variables could be related to the age of the respondents, as the process of primary socialisation imbued with gender stereotypes still does not overlap secondary socialisation. These trends should be monitored during late childhood since at this age children are cognitively plastic, but also vulnerable and influenceable by surrounding stimuli. This research approach, especially if extended to a wider geographical scale, can provide important knowledge to support the relational well-being of children and equal opportunities of society as a whole.