Objective To study the association between depression during pregnancy and low birth weight in neonates, and to provide a scientific basis for the prevention of low birth weight. Methods Cohort studies on the association between depression during pregnancy and low birth weight were collected and a Meta analysis was performed. Data were extracted independently by two investigators, and quality assessment was performed according to Newcastle-Ottawa Scale. The Egger's test was used to evaluate publication bias. Results A total of 12 cohort studies with 37 192 samples were included. The results of the Meta analysis showed that depression during pregnancy was associated with low birth weight (Z=2.08, P=0.038), and the neonates whose mothers had depression during pregnancy tended to have a high risk of low birth weight (RR=1.303, 95%CI:1.015-1.672). The sensitivity analysis showed that the results of this Meta analysis were stable and reliable, and the Egger's test showed no publication bias. Conclusions Depression during pregnancy may be a risk factor for low birth weight in neonates.