Adolescent and young mothers transitioning from pregnancy to postpartum need to maintain an optimal quality of life. Stress and exposure to violence (e.g., intimate partner violence (IPV), nonpartner violence) are predictors of poor quality of life for adult women; however, these associations remain understudied among adolescent and young mothers in urban areas. Guided by the social ecological model, the current study created a latent variable, urban social stress, to examine the impact of the urban social environment (i.e., stressful life events, discrimination, family stress, and neighborhood problems) on the quality of life of adolescent and young mothers during both pregnancy and postpartum. The current study is a secondary data analysis of a prospective cohort study of 296 expectant young mothers recruited at obstetrics and gynecology clinics. Results from structural equation and multigroup models found that higher urban social stress predicted lower mental and physical quality of life during pregnancy, but these associations were significantly stronger for IPV-exposed and nonpartner violence-exposed mothers. In the postpartum period, higher urban social stress predicted lower mental and physical quality of life, but these associations were significantly stronger for IPV-unexposed and nonpartner violence-exposed mothers. Stress reduction programs need to help adolescent and young mothers in urban areas develop stress management skills specific to urban social stress. Pregnancy and parenting programs need to be tailored to the specific needs of young mothers in urban areas by becoming sensitive to the role of IPV and nonpartner violence in these young women's lives.