IntroductionNowadays, most rectal tumours are treated open or minimally invasive, using laparoscopic, robot-assisted or transanal total mesorectal excision. However, insight into the total costs of these techniques is limited. Since all three techniques are currently being performed, including cost considerations in the choice of treatment technique may significantly impact future healthcare costs. Therefore, this systematic review aims to provide an overview of evidence regarding costs in patients with rectal cancer following open, laparoscopic, robot-assisted and transanal total mesorectal excision.Methods and analysisA systematic search will be conducted for papers between January 2000 and March 2022. Databases PubMed/MEDLINE, EMBASE, Scopus, Web of Science and Cochrane Library databases will be searched. Study selection, data extraction and quality assessment will be performed independently by four reviewers and discrepancies will be resolved through discussion. The Consensus Health Economic Criteria list will be used for assessing risk of bias. Total costs of the different techniques, consisting of but not limited to, theatre, in-hospital and postoperative costs, will be the primary outcome.Ethics and disseminationNo ethical approval is required, as there is no collection of patient data at an individual level. Findings will be disseminated widely, through peer-reviewed publication and presentation at relevant national and international conferences.Trial registration numberCRD42021261125.