Generic quality of life instruments may fail to capture the disease-specific challenges experienced by individuals with morbid obesity. The Laval questionnaire was developed to assess quality of life specifically in this population. This study aimed to translate and culturally adapt the Laval questionnaire into Persian and to evaluate its reliability and validity among Persian-speaking individuals with morbid obesity. The study was conducted at Shariati Hospital, a major bariatric surgery center in Tehran, Iran. Participants aged 19 to 65 years with morbid obesity who were candidates for bariatric surgery based on international criteria were recruited through consecutive sampling.

Results

The Persian version demonstrated excellent content validity, with a CVI greater than 0.9 and a CVR exceeding 0.8. The overall Cronbach’s alpha was 0.896, indicating strong internal consistency. Each domain showed a Cronbach’s alpha above 0.8, except for the sex life domain, which showed moderate consistency. All ICC values were statistically significant (p < 0.001), confirming excellent test–retest reliability. These findings support the Persian adaptation of the Laval questionnaire as a reliable and valid instrument for assessing quality of life among individuals with morbid obesity in Iran.