Within the context of a transdiagnostic perspective, the Psychological Inflexibility (PI) construct refers to rigid attempts to control undesirable private events at the expense of value-guided actions. Given the framework of PI as a construct associated with poor recovery and social functioning in people with psychosis, the main objective was to explore the role of two processes related to inflexibility (experiential avoidance, -EA-, and self-concealment) in predicting social functioning. The study sample of 103 patients with chronic psychosis was administered the Acceptance and Action Questionnaire-II, the Self Concealment Scale, and the Social Functioning Scale as the main measures. The differential weight of insight and clinical impression, also associated with social functioning, was analyzed by regression analysis. The results showed that private experiences led to rigid patterns of PI in people with psychosis and that the process that best predicted social functioning in these patients was EA, which explained 21.6% of the variance. EA, chronicity and global clinical impression together explained 35.2% of the variance. These results contribute to progress in understanding the role of PI in psychosis, as well as associated factors. The use of strategies facilitating acceptance, and not elimination of psychotic experiences, may be a possible strategy for addressing the impaired daily functioning of these patients.