ABSTRACT Adaptation and validation of the Frustration Tolerance Scale (ETF) in Peruvian children. The rate of bullying is high in Peru. Level of child frustration is one of the psychological factors involved in child aggression. However, there are few instruments available to assess frustration in Peruvian children. The purpose of this article was to adapt and validate the Frustration Tolerance Scale (FTS) for its use in the Peruvian child population. There were 796 children between 8 and 12 years old (M = 9.79, SD = 1.25, 49.70% were girls), from five private and public educational institutions in Metropolitan Lima and Callao, in Peru. Exploratory factor analysis (AFE) (n = 160), confirmatory factor analysis (CFA) (n = 636), reliability analysis and factorial invariance were used to verify the equivalence by gender. The AFE revealed the unidimensionality of the scale, which explained 48...