The objective of this study was to adapt and validate the Work-Related Acceptance and Action Questionnaire (WAAQ, Bond et al., 2013) so it can be used to measure psychological flexibility in the academic environment of a university of Ecuador. The study sample comprised 6,230 students. The instrument demonstrated high internal consistency (α= .90, ω= .91). The analysis of the main components showed a single factor, which explained 62.3% of the variance. The confirmatory factor analysis showed a satisfactory fit of the model. The correlations between WAAQ and the Acceptance and Action-II Questionnaire (AAQ-II, Bond et al., 2011) and Wallston’s Personal Competence Scale (Wallston, 1992) suggest that the questionnaires evaluate different constructs. Based on these results, it was concluded that the WAAQ is a valid and reliable instrument for measuring psychological flexibility in the Ecuadorian university academic environment.