Attention to children is one of the most important components of sustainable development of the city, since children are the most vulnerable members of society, therefore, a city suitable for children is suitable for all age groups, and sustainable development of the city requires planning safe cities appropriate for children. The aim of the present study is to present a child-friendly city model based on the regions of Mashhad. In this regard, three regions one, six and sixteen were selected, representing regions with high, medium and low levels of development. The sample size of the parent group was 382 people, the expert group was 85 people and the group of children aged 6 to 12 was 375 people. The research variables were also presented in the form of eight main indicators of participation, access to services, education, safety, quality of a healthy environment, children's security, home and family, and urban spaces and play. Data analysis was carried out in two parts: analysis of questionnaires of parents and experts using SPSS statistical software and analysis of children's interviews using the grounded theory method. The results of the study indicate that the status of child-friendly city indicators in high and medium development areas is not highly desirable and is undesirable in low development areas. The results also show that the status of child-friendly city indicators in the three development areas is different in the eyes of experts and parents, and experts have more optimistic views than parents' realism, but these indicators do not differ in the eyes of children in the three development areas due to the pure nature of the child and they all have similar aspirations. Finally, the child-friendly city model is presented in the form of four characteristics of a child-friendly city: education, nature, play, and health.