Self-monitoring is the extent to which individuals regulate self-presentation for the sake of desired public appearances. Snyder developed a Self-Monitoring Scale to measure individual differences on this construct. Since the measure could be insensitive to situational influences, it is uncertain whether the short-term self-monitoring elicited by certain social interactions could be examined. The present study explored the factor structures of a state self-monitoring scale which was adapted from 10 items of the Self-Monitoring Scale. Participants took part in an individual interview with an unfamiliar authority, and then completed the State Self-Monitoring Scale. Two samples of adolescents (N=98 and N=95) were tested. Exploratory factor analysis and confirmatory factor analysis using the two samples indicated that the 9-item State Self-Monitoring Scale had two stable factors. There was a statistically significant difference on State Self-monitoring between adolescents with high and low academic achievement, supporting the validity of the scale.