Background: Many observational services have been conducted to evaluate the risk factors of low birth weight, but the results showed no consistency. Therefore, we conducted this meta-analysis to investigate the association between endometriosis (body mass index) and the risk of low birth weight. Methods: Relevant works that were published in major international electronic databases such as PubMed, Scopus, Web of Science, LILACS, SciELO, and Cochrane were systematically searched until February 2018. Begg’s and Egger’s tests were used to determine publication bias in included studies. The random-effects model was carried out to determine the odds ratio. Results: A meta-analysis of the 12 studies proposed a significant association between endometriosis and the risk of low birth weight (odds ratio = 1.34, 95% confidence interval = 1.08–1.60). The subgroup analysis was carried out based on the design, adjusted form, and use of assisted reproductive technology in studies. The pooled results based on subgroup analysis in case–control and cohort studies were 1.46 (0.79–2.12) and 1.32 (1.02–1.62), respectively. There was significant correlation between endometriosis and low birth weight in cohort studies. Also, heterogeneity was not reported among studies in the subgroup based on adjusted form. There was no significant correlation between endometriosis and low birth weight in studies using assisted reproductive technology methods Conclusion: The systematic review and meta-analysis showed that endometriosis increases the risk of low birth weight. Therefore, it is a risk factor for low birth weight.