Background: Spontaneous intragastric balloon hyperinflation (SIBH) is a rare and concerning complication of intragastric balloons (IGBs). The mechanisms underlying SIBH remain unclear. This systematic review aims to synthesise the current evidence regarding the clinical presentation, management, complications, and hypothesised aetiologies of SIBH. Methods: A comprehensive literature search was conducted using PubMed, EMBASE, MEDLINE, and Ebsco databases. Studies reporting on cases of SIBH were identified and reviewed. Data points were extracted on patient presentation, management strategies, complications, outcomes, and proposed mechanisms. Results: Eighteen publications describing 29 patients with SIBH were included. The most common clinical presentation was gastric outlet obstruction (86%). Emergency endoscopy was required in 96% of cases, with balloon removal performed in 82%. Reported complications included acute pancreatitis and mucosal erosions; however, neither long-term morbidity nor mortality was observed. Microbial colonisation was hypothesised as the underlying cause in 62% of publications, supported by culture findings from balloon contents in 90% of cases, most commonly isolating gas-producing organisms such as Candida (80%) and anaerobic bacteria (40%). Conclusions: SIBH most frequently presents with gastric outlet obstruction and typically necessitates emergency endoscopic intervention. Gas-producing microbial colonisation of the balloon is the predominant hypothesised aetiology. Preventive strategies targeting microbial colonisation may be crucial in reducing the incidence of SIBH.