Assessment of procedural distress is essential at assisting children during invasive dental treatments. This study aimed to determine the validity and reliability of galvanic skin response as a measure for assessment of dental anxiety in children. 151 children, aged 5-7 years, participated in this study. Similar dental treatments were rendered to all subjects. At the beginning and end of the session, modified child dental anxiety scale (MCDAS), clinical anxiety rating scale (CARS) and galvanic skin response (GSR) were used to determine children?s anxiety. GSR was significantly correlated with both MCDAS (rs=0.62, p=0.02) and CARS (rs=0.44, p=0.032). The correlation between MCDAS and CARS was also significant (rs = 0.9, P<0.001). Anxiety decreased during the session in both GSR (rs=0.52, p=0.001) and MCDAS scales (rs=0.77, p=0.001). CARS also showed a reduction between the initial and second assessment, but it was not statistically significant (rs=0.12, P=0.36). The findings suggest that GSR is a reliable and valid measure for assessment of children?s dental anxiety in the clinical context. GSR may help to identify clinically anxious children before dental treatment to provide appropriate interventions.