Purpose: Prehabilitation has been suggested to reduce postoperative morbidity following colorectal cancer surgery; however, its effectiveness is unclear. This review aims to investigate the effectiveness of prehabilitation in reducing postoperative complications and length of stay in patients undergoing surgery for colorectal cancer. Methodology: A search was conducted in six medical databases from inception to April 2023. Randomised trials describing the effectiveness of prehabilitation (exercise, nutrition, psychological) compared to standard of care in colorectal cancer patients undergoing surgery were identified. Risk of bias was assessed using the revised Cochrane risk of bias tool. Meta-analyses were used to pool outcomes, and GRADE was used to determine the quality of evidence. Results: This review identified 23 trials (including 2475 patients) of multimodal (3), exercise (3), nutrition (16), and psychological (1) prehabilitation. There was moderate-quality evidence that preoperative nutrition significantly reduced postoperative infectious complications (relative risk: 0.65; 95% CI: 0.45 to 0.94) and low-quality evidence on reducing the length of hospital stay (mean difference: 0.87; 95% CI: 0.17 to 1.58) compared to control. No effect was found in other modalities. Conclusion: Prehabilitation of nutrition interventions demonstrated significant effect in reducing infectious complications and length of stay. Whether other prehabilitation modalities improve postoperative outcomes after colorectal cancer surgery is uncertain, as the current quality of evidence is low. Future trials may change our confidence in results and effect estimates in prehabilitation for colorectal cancer patients.