Objective: Identify the main causes of weight regain after bariatric surgery. Method: For this study, research was carried out in magazines and websites that compile scientific articles, namely Scielo, Pubmed, Capes. This systematic review provided scientific coverage in Portuguese and English, with the delimited period from 2013 to 2024 collecting twenty articles, five of which were discarded for being inconclusive or incomplete. Result: fifteen studies that make up this systematic review, of which 11,559 patients were evaluated after bariatric surgery, with an average of 84% female and the time of beginning of weight regain occurring on average after 3 years of procedure. Discussion: Selected studies highlight that weight regain after bariatric surgery involves a complex phase, occurring at different periods after surgery. Weight recovery can occur between 1 year and 5 years, with an average of 3 years post-procedure, and continuous long-term and individualized monitoring by a multidisciplinary team is extremely important. Studies point to the main causes related to weight regain: behavioral eating errors Monitoring a multidisciplinary team for the patient after bariatric surgery is essential, through this support the patient will receive guidance on food consumption, psychological and psychiatric support, in addition to clinical or surgical medical interventions if necessary. In this way, it will be possible to maintain weight loss and improve quality of life with the effective success of bariatric surgery. It must be emphasized that to achieve successful weight loss and maintenance after bariatric surgery, the patient must be aware to seek changes in lifestyle and opt for good choices throughout life.