ObjectiveThe objective of this study paper was to culturally adapt and validate the 22‐item Sino‐Nasal Outcome Test (SNOT‐22) questionnaire for Moroccan Arabic speaking patients.Study DesignProspective cohort study.SettingTertiary referral center; Ibn Rochd University Hospital, Casablanca, Morocco.Subjects and MethodsThe SNOT‐22 was conducted in patients with chronic rhinosinusitis (CRS) undergoing sinonasal surgery and in healthy volunteers, from January 2012 to December 2013. It was translated into Moroccan Arabic language. To evaluate this questionnaire, internal consistency, test‐retest reliability, responsiveness to treatment, and validity were analyzed.ResultsPreoperative SNOT‐22 scores were completed by 88 patients. Six‐month postoperative SNOT‐22 scores were available for 74 patients. The Cronbach’s alpha coefficient for the SNOT‐22 was 0.968, indicating high internal consistency. The test‐retest reliability coefficient was 0.993, indicating high reliability when administering the instrument on repeated occasions. The Moroccan version of the SNOT‐22 was able to highly discriminate between patients with CRS and group of healthy volunteers (P <. 0001). There was a statistically significant reduction in patient reported SNOT‐22 scores at 6 months after surgery (P <. 0001).ConclusionThe present study has found the Moroccan version of SNOT‐22 to be valid and easy to use with good reliability, validity, and responsiveness. It can be used to measure the impact of CRS on the patient’s quality of life and may also be used to evaluate CRS treatment.