Objective: Coping flexibility is strongly associated with individuals’ well-being when coping with trauma. However an instrument to measure emotional flexibility, a specific type of coping flexibility, is yet to be developed. The present study reported the development and validation of a Self-Administered Inventory on emotional flexibility. The study also explored the relationship between emotional flexibility and psychological well-being in adolescents who had experienced the 2008 Sichuan earthquake in China. Method: A sample of 327 adolescents from Beijing was recruited for item development and preliminary validation. Another sample of 941 middle school students from areas affected by the Sichuan earthquake was recruited for further validation and examination of its relationship with psychological well-being. Exploratory factor analysis and confirmatory factor analysis were used to examine the construct validity of the scale. The criterion validity of the measure was assessed using Pearson’s correlation coefficient. Results: The Emotional Flexibility Scale comprises 10 items covering 3 dimensions, namely tuning of positive emotions, emotion communication, and tuning of negative emotions. Emotional flexibility was positively correlated with cognitive flexibility and psychological well-being. Conclusions: The Emotional Flexibility Scale provides a brief, reliable, and valid measure of emotion regulation ability of adolescents faced with disasters.