Background: Low anterior resection syndrome (LARS) is a distressing complication following sphincter-preserving rectal resection that can significantly impair quality of life. Transanal irrigation (TAI) has been proposed as a treatment. This systematic review and meta-analysis evaluated the effectiveness of TAI for established LARS. Methods: PubMed, Embase and Cochrane Library were searched for studies evaluating TAI in patients with established LARS after rectal cancer surgery. Studies without established LARS, including patients with a stoma, or lacking baseline comparator data were excluded. Outcomes included bowel function, quality of life and feasibility measures. Risk of bias was assessed using the Mixed Methods Appraisal Tool. Random-effects meta-analysis was performed for change in LARS score where possible, with comparative and uncontrolled data analysed separately. The 3–6 month timepoint was prioritised for quantitative synthesis where multiple follow-up timepoints were reported. Results: Twelve studies were included (six case series, one cohort study and five randomised trials), comprising 436 patients. Risk of bias was generally moderate. Narrative synthesis demonstrated consistent improvement in bowel function symptoms, with reported improvements in quality of life and patient satisfaction, although outcome measures were heterogeneous. Six studies contributed to meta-analysis. Uncontrolled pre–post analysis showed a pooled mean change in LARS score of −18.0 points (95% CI −22.3 to −13.7; I²=84%). One randomised trial demonstrated lower LARS score at 6 months with TAI compared with conservative management (mean difference −11.3; 95% CI −17.1 to −5.6). Conclusion: TAI is associated with clinically meaningful improvement in LARS score and may improve quality of life and patient satisfaction. Further well-reported randomised trials are required to confirm comparative effectiveness and durability of benefit.