Children with autism spectrum disorder (ASD) are frequently afflicted with sensory processing difficulties, which often impact their ability to cooperate with dental treatment. The objective of this pilot study was to determine the effects of green light exposure on behavior, pain, distress and anxiety in pediatric patients with ASD undergoing a dental prophylaxis. Twelve children diagnosed with ASD, aged 6-17 years, requiring a dental prophylaxis participated in this study. Participants completed two dental prophylaxes, three months apart, one in a standard white light -exposed dental operatory and one in a green light -exposed dental operatory. Behavioral cooperation, pain intensity, physiological stress and anxiety were assessed in all patients. The Wilcoxon matched -pairs signed rank test was used to estimate differences in measured outcomes according to the experimental condition. There was a trend towards reduced uncooperative behavior when children received a dental prophylaxis in the green lightexposed operatory ( p = 0.06). Similar levels of heart rate variability ( p = 0.41), salivary alpha amylase ( p = 0.19), and salivary cortisol ( p = 0.67) were observed at the start and end of each visit in both conditions. Green light exposure had no significant effect on pain intensity ( p = 0.17) or behavioral anxiety ( p = 0.31). These findings suggest a preliminary positive benefit of green light exposure on behavioral outcomes in pediatric patients with ASD and warrants a further, large-scale clinical trial.