Parents of children with autism spectrum disorder (ASD) show increased levels of parenting stress, but only one study has examined this association before a diagnostic evaluation. We conducted a cross-sectional study of parenting stress in 317 low SES parents with children at-risk for ASD before a diagnostic evaluation. Multiple regression modeling evaluated the associations between parenting stress and parent and child factors. Parenting stress was negatively associated with social support and positively associated with active avoidance coping and parental worry. However, parenting stress was not associated with the child's ASD symptom severity or adaptive functioning, except for self-direction. Findings suggest parenting stress among parents of children at risk of ASD should be assessed prior to diagnosis. [This study was conducted in collaboration with the Developmental and Behavioral Pediatrics Research Network (DBPNet).]