Three studies evaluated psychometric properties of the Dutch version of the 9-item Acceptance and Action Questionnaire (AAQ)—a self-report measure designed to assess experiential avoidance as conceptualized inAcceptance and Commitment Therapy (ACT). Study 1, among bereaved adults, showed that a one-factor model, with AAQ-items constituting a single dimension of experiential avoidance, fitted the data well. The internal consistency and temporal stability of the AAQ were satisfactory. In Study 2, among undergraduate students, and Study 3, among 60 outpatients, higher AAQ scores were found to be significantly associated with psychopathology, maladaptive coping strategies, and neuroticism, attesting to the validity of themeasure. In support of its incremental validity, Study 3 showed that the AAQ remained significantly associated with depression and anxiety after controlling for neuroticism and thought suppression. The current studies complement prior research supporting the psychometric properties of the AAQ and the ACT conceptualization of experiential avoidance.