Juvenile Fibromyalgia (JFM) is poorly known, leading to delay in the identification of the syndrome. On the other hand, early diagnosis in children is important to prevent the worsening of the disease. This study aims to estimate the prevalence of JFM in an Italian population-based convenience sample, using different criteria (2010 and 2016 ACR, Yunus and Masi), by involving family pediatricians. It also aims to assess the relationships between JFM and contextual factors of the children and their parents, as well as to raise awareness of JFM among pediatricians. Children’s data were collected using an ad hoc electronic questionnaire. Overall, 7275 questionnaires were collected (48.5% females; mean age: 8.2 ± 3.6 years). Thirty-eight children (0.5%) met the 2010 ACR criteria, and 4 (0.1%) met the 2016 ACR criteria. The likelihood of meeting the 2010 ACR criteria was significantly higher for children older than 8 years (OR: 2.42), those who had injuries during the leisure time that caused persistent pain (OR: 6.49), whose parents (at least one) had a diagnosis of fibromyalgia (OR: 2.54) or diffuse pain (OR: 9.09). In conclusion, 2010 ACR criteria are confirmed as the more appropriate for children and adolescents and the analysis of contextual factors suggests the need for family pediatricians to pay particular attention to the most important predictors of JFM.