Bariatric surgery is increasingly being used to treat severe obesity, but little is known about its impact on patient-reported outcomes (PROs). For PRO data to influence practice, well-designed and reported studies are required. A systematic review identified prospective bariatric surgery studies that used validated PRO measures. Risk of bias in randomized controlled trials (RCTs) was assessed, and papers were examined for reporting of (i) who completed PRO measures; (ii) missing PRO data and (iii) clinical interpretation of PRO data. Studies meeting all criteria were classified as robust. Eighty-six studies were identified. Of the eight RCTs, risk of bias was high in one and unclear in seven. Sixty-eight different PRO measures were identified, with the Short Form (SF)-36 questionnaire most commonly used. Forty-one (48%) studies explicitly stated measures were completed by patients, 63 (73%) documented missing PRO data and 50 (58%) interpreted PRO data clinically. Twenty-six (30%) met all criteria. Although many bariatric surgery studies assess PROs, study design and reporting is often poor, limiting data interpretation and synthesis. Well-designed studies that include agreed PRO measures are needed with reporting to include integration with clinical outcomes to inform practice.