Background Perioperative telemonitoring of patients undergoing major surgery might lead to improved postoperative outcomes. The aim of this systematic review is to evaluate the effectiveness of current perioperative telemonitoring interventions on postoperative clinical, patient-reported, and financial outcome measures in patients undergoing major surgery. Methods For this systematic review, PubMed, CINAHL, and Embase databases were searched for eligible articles published between January 1, 2009 and March 15, 2021. Studies were eligible as they described: (P) patients aged 18 years or older who underwent major abdominal surgery, (I) perioperative telemonitoring as intervention, (C) a control group receiving usual care, (O) any type of postoperative clinical, patient-reported, or financial outcome measures, and (S) an interventional study design. Results The search identified 2958 articles of which 10 were eligible for analysis, describing nine controlled trials of 2438 patients. Perioperative telemonitoring comprised wearable biosensors ( n = 3), websites ( n = 3), e-mail ( n = 1), and mobile applications ( n = 2). Outcome measures were clinical ( n = 8), patient-reported ( n = 5), and financial ( n = 2). Results show significant improvement of recovery time, stoma self-efficacy and pain in the early postoperative phase in patients receiving telemonitoring. Other outcome measures were not significantly different between the groups. Conclusion Evidence for the effectiveness of perioperative telemonitoring in major surgery is scarce. There is a need for good quality studies with sufficient patients while ensuring that the quality and usability of the technology and the adoption in care processes are optimal.