The reported incidence of trocar site hernias in bariatric surgery ranges between 0.5 and 3%. The best available evidence derives from retrospective studies analysing prospective databases, thus including only patients who presented with symptoms or received surgical treatment due to trocar site hernias after a laparoscopic bariatric procedure. A systematic literature research was conducted up until September 2017. Search strategies included proper combinations of the MeSH terms 'laparoscopy' and 'bariatric surgery', 'trocar/port' and 'hernia'. Searches were not limited by publication type or language. The review was registered in PROSPERO (ID 85102) and performed according to the PRISMA guidelines. Sixty-eight publications were included. Pooled hernia incidence was 3.22 (range 0-39.3%). Thirteen trials reported systematic closure of the fascia; 12 trials reported no closure. Data availability did not allow for pooling to calculate relative risk. Higher BMI and specific hernia examination using imaging modalities were associated with a significantly higher incidence of trocar site hernias. Studies dedicated to detection of TsH reported a pooled incidence of 24.5%. Trocar site hernias are an underestimated complication of minimally invasive multiportal bariatric surgery. While high-quality trials are not available allowing for a precise calculation of the incidence, existing data are indicative of very high incidence rates. Risk factors for developing a trocar site hernia in bariatric surgery have not yet been systematically analysed. Prospective studies in this field are necessary.