Missed appointments have a great economic, social and administrative impact on the management of public health services. This research aimed to study factors associated with non-attendance to the first appointments of pediatric patients in secondary dental care services in the city of Curitiba, Brazil. A cross-sectional study was performed using secondary data from the electronic health records of the Curitiba Municipal Secretary of Health. The study included all children (0-12 years) referred to secondary dental clinics in the years 2010 to 2013. Data were analyzed by the chi-square test and Pearson linear trend chi-square (α = 0.05). Binary logistic regression models were built. Data from 1,663 children were assessed and the prevalence of non-attendance was 28.3%. The variables associated with the non-attendance in inferential analysis (p < 0.05) and in the final model were the household income per capita (95% CI: 1.93-2.82) and the waiting time in virtual queue (95% CI: 1.000-1.002). Socioeconomic aspects and the waiting time in virtual queue, should be considered in the strategic planning of health services as they may influence the attendance of pediatric patients in secondary dental referral service.