The aim of the present study was to explore the characteristics of psychotropic treatment and of psychosocial functioning associated with self-reported medication adherence in persons with psychosis engaged in rehabilitation. The study was performed in the REHABase cohort including persons referred to a French network of psychosocial rehabilitation centers. Treatment adherence was assessed using the Medication Adherence Rating Scale (MARS). The associations between MARS score (categorized as “low” < 7 vs. “high” ≥ 7) and functioning or psychotropic treatment characteristics were explored using multivariate analyses in 326 participants with schizophrenia spectrum disorders. Regarding psychotropic treatment, high anticholinergic load was the only characteristic associated with poor medication adherence (adjusted OR, aOR 1.98, 95% CI 1.07–3.66). Regarding functioning measures, participants with poor medication adherence were more likely to present with lower stage of recovery (aOR 2.38, 95% CI 1.31–4.32), poor quality of life (aOR 2.17, 95% CI 1.27–3.71), mental well-being (aOR 1.68, 95% CI 1.03–2.72) and self-esteem (aOR 1.74, 95% CI 1.05–2.87), and higher internalized stigma (aOR 1.88, 95% CI 1.09–3.23). Self-reported poor medication adherence is a marker of poor functioning in persons with psychosis. The MARS is a quick and simple measure of adherence that may be helpful in clinical and rehabilitation settings to identify persons with specific rehabilitation needs.< Réduire