Laparoscopic Sleeve gastrectomy (LSG) is the most commonly performed bariatric surgical procedure worldwide. There is wide variation however in post-operative weight loss on long term follow-up, and residual gastric volume (RGV) is believed to be an important variable. Multiple studies have correlated RGV as assessed by Computerized Tomography volumetry with excess weight loss (EWL%) following LSG, but definite consensus is lacking. This article systematically reviews the published studies in English literature to ascertain whether any correlation exists between the RGV and EWL% following LSG. Ten studies were included in this review, and significant differences were noted in the technique of RGV assessment, and timing of RGV and EWL% assessment. Five studies found a statistically significant correlation between the RGV and EWL%. One study found a correlation which did not reach statistical significance. Two additional studies reported that the resected volume rather than RGV correlated with the EWL%. Meta-analysis of studies reporting correlation between RGV and EWL% showed that up to 26.3% (95% CI: 5.1%-56.1%) of variability in EWL% can be explained by variations in RGV. A lower RGV is likely to result in a better post-operative weight loss following LSG. There is need for standardization of technique and timing of RGV assessment. © 2020 World Obesity Federation.