We searched the Cochrane Library, MEDLINE, EMBASE, AIDSearch, and Gateway to assess the effect of prenatal and/or postnatal vitamin A supplementation on the risk of mother-to-child transmission (MTCT) of HIV and other pregnancy outcomes. We included 5 trials totaling 7528 women (4 trials of prenatal and 1 trial of postnatal supplementation). Overall, there was no evidence of an effect of prenatal and/or postnatal vitamin A supplementation on the risk of MTCT of HIV (Relative Risk [RR] 1.06, 95% Confidence Interval [CI] 0.89-1.26). However, prenatal vitamin A supplementation significantly improved birth weight (weighted mean difference 89.78; 95% CI, 84.73-94.83), but there was no evidence of an effect on stillbirths (RR 0.99; 95% CI, 0.68-1.43), preterm births (RR 0.88; 95% CI, 0.65-1.19), death before 24 months among live births (RR 1.08; 95% CI, 0.91-1.29), and maternal death (RR 0.83; 95% CI, 0.59-1.17). The available evidence does not support vitamin A supplementation of HIV-infected pregnant and lactating women, despite improvement in birth weight.