Neoplasia in the Gila monster (Heloderma suspectum) is not commonly investigated, and literature regarding the prevalence and type of neoplasms that affect this species is sparse. Gastrointestinal tract adenocarcinoma (GTA) in particular has only been reported twice in Gila monsters, once in the small intestine and once in the colon. In this case series, 50% (7/14) of the Gila monsters presented to the pathology service at Smithsonian's National Zoo and Conservation Biology Institute (SNZCBI) over the span of 26 yr (1997–2023) were found to have intestinal and/or colonic adenocarcinoma. The frequency of GTA reported in this collection likely represents a multifactorial etiology including geriatric age of specimens, chronic inflammation, gastrointestinal tract infection, and/or increased cognizance of the disease because of previous reports within the collection. An increased awareness of GTA in this species may lead to improved recognition of the disease.