Psychological flexibility is a primary factor for mental health and is the main process addressed within Acceptance and Commitment Therapy (ACT). In this sense, different instruments have been created to measure this variable. However, their limitations are resolved with the Psy-Flex, a brief instrument that measures psychological flexibility from its six components and demonstrates adequate psychometric properties. Therefore, the present study aims to validate the Psy-Flex in the Peruvian population from a network analysis. The sample comprised 1040 participants, and the translation of the Psy-Flex from a previous study in Latin America was used, along with the PHQ-2, GAD-2, and MLQ, which had been previously validated in Peru. Additionally, content validity was assessed. The Exploratory Graph Analysis (EGA) determined the unidimensionality of the Psy-Flex, as well as the stability of the items, structural consistency, validity of other variables, and measurement invariance across gender. In conclusion, the results of adapting the Psy-Flex in Peru enable us to accurately measure psychological flexibility due to its brevity, sensitivity, psychometric evidence, and relevance.