Parents are critical for early detection of autism; however, children of low SES are identified later than their counterparts. Such delays in detection of autism may be attributed to limited parental knowledge of early developmental milestones and early signs of autism. Authors examined knowledge of developmental milestones and autism in 41 parents of low SES with low literacy. Participants were recruited from adult literacy programs and completed measures of developmental milestones and autism knowledge. Parents reported greater knowledge of motor milestones when compared to other milestones, including language, cognitive, social, and play milestones. Parent knowledge of milestones did not correlate with knowledge of autism. Parents overestimated social and play milestones that indicate autism risk, such as delays in responding to name and pointing to show interest, which may contribute to delays in detection of autism. Authors discuss implications of the results in terms of areas of future research.