Objective: To investigate the association between maternal posttraumatic stress disorder (PTSD) and infant development in a South African birth cohort. Method: Data from the Drakenstein Child Health Study were analyzed. Maternal psychopathology was assessed using self-report and clinician-administered interviews; and 6-month infant development using the Bayley III Scales of Infant Development. Linear regression analyses explored associations between predictor and outcome variables. Results: Data from 111 mothers and 112 infants (1 set of twins) were included. Most mothers (72%) reported lifetime trauma exposure; the lifetime prevalence of PTSD was 20%. Maternal PTSD was significantly associated with poorer fine motor and adaptive behavior – motor development; the latter remaining significant when adjusted for site, alcohol dependence, and infant head-circumference-for-age z score at birth. Conclusion: Maternal PTSD may be associated with impaired infant neurodevelopment. Further work in low- and middle-income populations may improve early childhood development in this context.