Metabolic Bariatric Surgery (MBS) is increasingly gaining ground, given that it constitutes the most effective treatment of obesity and associated health problems, with enduring results and a well-documented safety profile. Nevertheless, certain issues may rise in the medium and long term. Among them, there is a heterogeneous group of complications under the umbrella term “post-bariatric hernia”, including internal hernias, abdominal wall hernias, and hiatal hernias. Internal hernias constitute the most studied category, but evidence on the other categories is not lacking. This chapter will attempt to cover diagnostic, treatment, and preventive aspects in the management of hernia post-MBS following a comprehensive, evidence-based approach. In brief, with regards to the prevention of internal hernias, suturing of all defects is strongly recommended for Roux-en-Y Gastric Bypass (RYGB), but the evidence is less clear when it comes to newer bypass procedures, such as One-Anastomosis/Mini Gastric Bypass (OAGB/MGB) and Single Anastomosis Duodenal-Ileal Bypass (SADI). As far as abdominal wall hernias are concerned, there is no clear evidence of the advantages of suture closure against non-closure. Finally, with respect to hiatal hernias post-MBS, the caveat rests in the documentation of de novo versus pre-existing hiatal hernia, which mandates meticulous preoperative evaluation of symptoms and potentially further endoscopic documentation.