Aim: To assess the development of high dental anxiety and the factors that are associated with it over a 2-year period. Design: This longitudinal study focused on 416 Brazilian children aged 5-7 years over 2 years. Interviews were conducted with the children's parents to investigate the children's health-related behaviours. Additionally, the children's dental caries experience was clinically evaluated to obtain information about DMFT/dmft (decayed, filled and missing teeth) indices. Using the Dental Anxiety Question, children whose parents responded “yes” to the prompt “Is he/she very afraid of going to the dentist?” were classified as having high dental anxiety. Multilevel mixed-effects logistic regression was used to analyse factors to determine the extent to which they were associated with high dental anxiety longitudinally. Results: The prevalence of high dental anxiety in children at baseline was 16.2%, whereas it was 19.8% at follow-up. Additionally, 38% of the children with high dental anxiety at baseline still had the condition after two years, although 62% of them no longer had high dental anxiety. The incidence of high dental anxiety at 2-year follow-up was 15.0%. Children who used medication chronically had a 2.1 times greater likelihood of having high dental anxiety. Furthermore, children whose parents reported high dental anxiety had a 2.6 times greater likelihood of having high dental anxiety themselves. A one-unit increase in a child's dmft score increased the risk of high dental anxiety by 1.1 times at follow-up. Conclusion: After two years, the incidence of high dental anxiety was 15.0%. Poor oral health, unstable general health and parents with high dental anxiety were factors that were associated with this type of anxiety in schoolchildren. It is important that dentists are aware of children's high dental anxiety and the associated factors so that they can appropriately intervene. Dentists fulfil an important role and should stimulate and promote good general hygiene habits that may prevent future problems.