This case series describes a possible link between perforation during gastrointestinal tract (GIT) endoscopy in cats and a specific underlying condition. GIT endoscopy is commonly performed in cats, with a total of 254 endoscopies performed at a UK referral centre from 1 January 2015 to 31 December 2019. During this period, three cases were reported to have GIT perforation in conjunction with the procedure. All three cases described were diagnosed with alimentary lymphoma of varying location and histological grade. One case suffered colonic perforation and was euthanased, while the other two underwent exploratory coeliotomy. Both surgeries were successful. Of the cats that underwent surgery, one was diagnosed with lymphoplasmocytic inflammation at the perforation site and low-grade/small cell lymphoma distally, and subsequently treated with prednisolone and chlorambucil, while the other was diagnosed with intermediate-grade lymphoma at the perforation site, and the owners elected for euthanasia upon diagnosis.