Mucous membrane pressure injury (MMPI) is associated with a history of medical device use at the site of injury. The current international guideline recommends they should be reported in incidence and prevalence studies. The aim of this systematic review was to analyse the incidence and prevalence of hospital-acquired MMPI in adults admitted to acute hospital settings. Database searches (EBSCO CINAHL Complete, EBSCO Medline Complete, Embase, Scopus and Web of Science) were undertaken between October 2019 and February 2021, using search terms related to hospital-acquired, mucosal and device-related pressure injury/ulcer incidence and prevalence. Searches were limited to the English language. Articles published between 2008 and 2020, reporting incidence or prevalence of mucous membrane or medical device-related pressure injury in non-interventional samples were selected. Two authors assessed study bias and extracted data, with a third reviewer as arbitrator. Twenty-one studies met inclusion criteria; most provided incidence data. No studies were found that specifically reported MMPI incidence or prevalence. It was possible to calculate incidence or prevalence from four studies; all were in intensive care settings. MMPI incidence of 0.8% and 30.4%, and prevalence of 1.7% and 3.7% were found. One study provided data that enabled calculation of prevalence of 0.1% in a non-intensive care sample. Only one other study provided specific data about MMPI. It is concluded that there is insufficient evidence available to enable estimation of MMPI incidence or prevalence in either acute hospital or intensive care settings.