Objective: Although atraumatic restorative treatment (ART) is considered to be a good option for anxious patients, there is a lack of information whether ART associated to oral health educational strategy (OHES) would positively influence the level of anxiety and stress in children. This study aimed to evaluate the impact of OHES on anxiety and stress markers of schoolchildren submitted to ART. Design: A sample of 78 six- to eight-year-old schoolchildren, with carious lesions in dentin, were randomly divided into groups: OHES + ART-group (n = 39) and ART-group (n = 39). OHES consisted of an educational interactive strategy performed once a week for four weeks. ART was performed using a standardized procedure with hand instruments and glass-ionomer cement. Anxiety and stress markers were assessed subjectively by the modified Venham Picture Test (m-VPT), modified Venham Anxiety Scale (m-VAS), while objective measures consisted of heart rate (HR) and salivary cortisol and alpha-amylase levels evaluated before, during and after treatment. Results: The two groups did not differ in the perceived anxiety and in anxious behavior, and the variation along the treatment was not significant in both groups (p > 0.05). Both groups also showed higher HR “Before ART-restoration” than the other time-points as an anticipatory anxiety. ART group showed higher HR than OHES + ART group during the “Explanation of procedure” (p = 0.041) and “Deep excavation” (p = 0.018), and only ART group showed higher amylase levels “Before ART” compared to “After ART” (p = 0.004). Conclusions: It was concluded that OHES associated with ART showed a positive effect in modulating heart rate and alpha-amylase levels, that is, those markers of stress objectively measured during ART-restoration.