Posttraumatic growth is the psychological capacity to perceive positive changes in the face of highly stressful or potentially traumatic events and may be especially useful in buffering their effects in the lives of adolescents. The aim of this study was to evaluate the psychometric properties of the Peruvian adaptation of the Posttraumatic Growth Inventory (PTGI). A total of 2103 adolescents (50.7% male) between 13 and 19 years of age, who were exposed to some highly stressful event in the previous five years, participated in the study. Confirmatory factor analysis, factorial invariance, network analysis and correlation of the PTGI with a measure of well-being were performed. The best parsimonious fit was observed in a 21-item unidimensional model, the PTGI was shown to be gender invariant, and network analysis determined a greater measure of strength centrality in item 2 (appreciation of life). These results indicate that the PTGI is a test with construct validity, invariant, reliable and adequate to evaluate the level of psychological growth in Peruvian adolescents who suffered some stressful event during the previous five years.