The objective of this study was to evaluate the relationship between psychosocial stress in pregnancy and negative perinatal outcomes and to identify key moderators of this relationship. To evaluate this relationship, a meta-analytic review was conducted of studies that prospectively assessed the relationship between psychosocial stress in pregnancy and perinatal outcomes. A total of 35 studies, written or published between 1991 and 2009, involving 31,323 women were located. The overall association between psychosocial stress and negative perinatal outcomes was significant, but negligibly small in size (r (35) = -0.04, CI = -0.08, -0.01). Examining specific perinatal outcomes, only the associations with neonatal weight (r (14) = -0.07, CI = -0.03, -0.01) and risk for low birth weight (r (5) = 0.07, CI = 0.03, 0.10) were statistically significant, but again, very small. Results support that psychosocial stress explains a negligible to very small amount of the variability in perinatal outcomes. Future research should focus on identifying other psychosocial and lifestyle variables that alone or in interaction with other factors explain larger amounts of the variability in perinatal outcomes. Future research should also examine whether psychosocial stress increases risk for negative outcomes in combination with other biomedical and psychosocial risk factors.